Academic literature on the topic 'Lymphocytes T [LT]'

AimsSclerosing lymphocytic lobulitis (SLL) of the breast is characterised by lymphocytic lobulitis, ductitis, vasculitis and dense keloidal fibrosis with epithelioid fibroblasts. However, the subsets of the infiltrating lymphocytes and their contribution to disease progression have not been fully explored.MethodsCD20, CD3, CD4, CD8 and regulatory T (Treg) lymphocytes were evaluated in the epithelial and vascular areas in SLL. The relationship between the lymphocyte subset in different regions and the degree of inflammation was analysed.ResultsLymphocytic infiltration was mainly located in peri-lobular, peri-ductal and peri-vascular areas. No significant differences between CD20 and CD3 lymphocytes were found in peri-epithelial areas. However, there were more intra-ductal/lobular epithelial CD3 than CD20 lymphocytes (p<0.001). For T lymphocyte subsets, more CD4 than CD8 lymphocytes were found in the peri-lobular/vascular regions (p≤0.026); but an opposite trend was seen in the intra-ductal/lobular regions (p<0.001). In the peri-lobular/vascular regions, generally, different lymphocyte subsets correlated with each other. Interestingly, in the peri-ductal region, only CD4 lymphocytes showed significant correlations with all other subsets (p≤0.020). Regarding their relationship with the degree of inflammation, significant positive correlations were observed for all subsets in peri-vascular/lobular regions (p≤0.045). Only regulatory T cells, but not the others, at the peri-ductal region showed significant correlation with the degree of inflammation at all three regions (p≤0.014).ConclusionsIn addition to B lymphocyte subsets, T lymphocyte subsets could be involved differently in SLL. CD4 lymphocytes may have a pivotal role in recruiting other subsets to the inflamed site, and triggered the cascade of inflammatory changes resulting in fibrosis.

ABSTRACT Adhesion molecules, which play a major role in lymphocyte circulation, have not been well characterized in human immunodeficiency virus (HIV) infection. T-lymphocyte populations, including CD3, CD4, CD28, and adhesion molecules (L selectin, LFA-1, VLA-4, and ICAM-1) were measured by flow cytometry in a cross-sectional study of 100 HIV-infected and 49 HIV-seronegative adults. HIV-infected adults had lower numbers of CD3+ lymphocytes expressing L selectin (P < 0.0001) and VLA-4 (P < 0.01) and higher numbers of CD3+ lymphocytes expressing LFA-1bright (P < 0.002) than did HIV-negative adults. By CD4+-lymphocyte count category (>500, 200 to 500, or <200 cells/μl), HIV-infected adults with more advanced disease had lower percentages of CD3+ lymphocytes expressing L selectin and VLA-4 and higher percentages of CD3+ lymphocytes expressing LFA-1. The percentages of CD3+ CD28+ lymphocytes and of CD3+L selectin+ lymphocytes were positively correlated (Spearman coefficient = 0.86; P < 0.0001), and the percentage of CD3+ CD28+ lymphocytes and the CD3+ LFA-1bright lymphocyte/CD3+LFA-1dim lymphocyte ratio were negatively correlated (Spearman coefficient = −0.92; P <0.00001). The results of this study suggest that HIV infection is associated with altered expression of adhesion molecules.

Objective: The aim of this work was to investigate the influence of T lymphocyte subsets and platelet-specific autoantibodies on immune thrombocytopenia (ITP) with dexamethasone therapy. Methods: The samples were obtained from patients before therapy. T lymphocyte subsets were measured by flow cytometry, and platelet-specific autoantibodies were evaluated by modified monoclonal antibody immobilization of platelet antigen assay. Results: A total of 50 ITP patients were involved in the study. Twenty-three were anti-GPIbα antibody positive and were treated with dexamethasone, with a response rate of 47.8%. Twenty-seven cases were anti-GPIbα antibody negative, with a response rate of 77.8%. A significant difference was detected (p < 0.05). The level of CD4+ T lymphocytes in ITP patients was lower compared with the control group (p < 0.05). The level of CD8+ T lymphocytes was higher than that in the normal controls (p < 0.05). Additionally, the patients with a higher level of CD8+ T lymphocytes and lower level of CD4+ T lymphocytes were more likely to respond to dexamethasone treatment. Moreover, we observed that ITP patients associated with anti-GPIIb/IIIa antibodies had lower levels of CD4+ T lymphocytes and higher CD8+ T lymphocyte levels. Conclusions: There was insensitivity to dexamethasone treatment in ITP patients who were anti-GPIbα antibody positive. The detection of T lymphocyte subsets is useful in ITP patients for forecasting the outcome of dexamethasone treatment. There were some relationships between the different antibodies and the levels of T lymphocyte subsets.

Unlike other leukemia types in which the bone marrow findings are diagnostic, the bone marrow pathology of T-cell granular lymphocytic leukemia (GLL) is subtle and ill-defined. In this study, bone marrow biopsy specimens from 36 patients with T-cell GLL and from 25 control patients with cytopenias and relative or absolute increases in blood large granular lymphocytes were studied by immunohistochemistry using antibodies to the cytolytic lymphocyte antigens CD8, CD56, CD57, TIA-1, and granzyme B. The goals were to clarify the bone marrow pathology of T-cell GLL and to refine the diagnostic criteria for T-cell GLL. Most bone marrow specimens from the T-cell GLL patients contained interstitially distributed clusters of at least 8 CD8+(83%) or TIA-1+ (75%) lymphocytes or clusters of at least 6 granzyme B+ (50%) lymphocytes. Interstitial clusters of CD8+, TIA-1+, or granzyme B+ cells were present in 36%, 12%, and 0%, respectively, of the control bone marrows (all values significantly different, P &lt; .001). An additional T-cell GLL disease-specific finding was the presence of linear arrays of intravascular CD8+, TIA-1+, or granzyme B+ lymphocytes, found in 67% of cases of T-cell GLL and in none of the 25 control samples (P &lt; .001). Staining for CD56 and CD57 was noncontributory. These findings clarify the bone marrow histopathology of T-cell GLL and provide an additional tool by which the discrete, abnormal lymphocyte population required for a diagnosis of T-cell GLL can be identified.

Introduction: When checking tumour growth, a number of observations indicate that the immune system plays a significant role in patients with renal cell carcinoma (RCC). Infiltration by lymphocytes (tumour infiltrating lymphocytes, TILs) is more prevalent in RCC than any other tumours. T lymphocytes are the dominant population of TIL cells. Views concerning the role of T lymphocytic subpopulations, B lymphocytes and NK cells in an anti-tumour response are not established. Aim: The aim is to determine the phenotype and activation of T and B lymphocytic subpopulations and NK cells and to compare their representation in tumour stroma and peripheral blood lymphocytes (PBL) in patients with RCC. Material and methods: Samples of peripheral blood taken from the cubital and renal veins and tumour stroma cells were obtained from 44 patients in the course of their surgeries carried out due to primary RCC. TILs were isolated from mechanically disintegrated tumour tissue. Immunophenotype multiparametric analysis of PBL and TILs was carried out. Their surface and activation characteristics were determined by means of flow cytometer. Results: CD3+ T lymphocytes (69.7 %) were the main population of TILs. The number of CD3+/CD8+ T lymphocytes was significantly higher in TILs, 42.6 % (p< 0.01), while CD4+ T lymphocytes were the majority population in peripheral blood, 41.35 % (p < 0.001). The representation of CD3+/69+ T lymphocytes was significantly higher in TILs, 32.9 %, compared to PBL (p<0.001). On the contrary, the numbers of CD3+/CD25+, CD8+/57+ and CD4+/RA+ (naive CD4+ T lymphocytes) were higher in PBL (p<0.001). The differences in representation of (CD3-/16+56+) NK cells and CD3+/DR+ T cells in TILs and PBL were not significant. Conclusion: The above-mentioned results prove that the characteristics and intensity of anti-tumour responses are different in compared compartments (tumour/PBL). CD3+/CD8+ T lymphocytes are the dominant lymphocytic population of TILs. The knowledge of the phenotype and functions of effector cells, which are responsible for anti-tumour response, are the basic precondition for understanding the anti-tumour immune response and the cause of its failure.

To explore the correlation between T lymphocytes and clinical severity in patients of COVID-19. A total of 183 COVID-19 patients were recruited in Shenzhen Third People’s Hospital from January 11 to February 16, 2020. According to the clinical classification criteria, they were divided into severe group (46 cases) and non-severe (137cases). T lymphocyte counts, lymphocyte subpopulation, IL-6 levels, and clinical outcomes were compared between the two groups. Compared with the non-severe group, the lymphocyte count, T lymphocyte count, T lymphocyte percentage, CD4+ T lymphocyte count, CD4+ T lymphocyte percentage, CD8+ T lymphocyte count, and CD8+ T lymphocyte percentage were lower in the severe group ( p < 0.05). Compared with the non-severe group, IL-6 were higher in the severe group ( p < 0.05). Compared with admission, the T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count were significantly increased upon discharge in severe patients, non-severe patients and all patients. Multivariate Logsitic regression analysis showed CD4+ T lymphocyte count (OR −0.011; 95% CI −0.041 to −0.001; p = 0.011), CD8+ T lymphocyte count (OR −0.14; 95% CI −0.048 to −0.003; p = 0.013) were closely correlated with the clinical severity in patients of COVID-19. Multivariate Logsitic regression analysis also showed CD4+ T lymphocyte count (OR −0.012; 95% CI −3.177 to 0.261; p = 0.021), CD8+ T lymphocyte count (OR −0.019; 95% CI −5.852 to 0.115; p = 0.004) were independent predictors of disease progressing to the composite endpoint. Subgroup analysis for critically ill patients: The T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count remained low in the death patients. The T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count recovered soon in the discharged patients. In the event of COVID-19 infection, the T-lymphoid system is the primary activated immune system. The T lymphocytes, CD4+ T lymphocytes, CD8+ T lymphocytes continued to be low may be significantly related to the deterioration of the disease, and may indicate a poor prognosis.

The present study was undertaken to examine the role of the exercise-induced stress hormone response on the regulation of type 1 and type 2 T lymphocyte intracellular cytokine production. Subjects performed 2.5 h of cycling exercise at 65% maximal O2 uptake while ingesting a 6.4% carbohydrate (CHO) solution, 12.8% CHO solution, or a placebo. Peripheral whole blood samples were stimulated and stained for T lymphocyte surface antigens (CD4 and CD8). Cells were then permeabilized, stained for intracellular cytokines, and analyzed using flow cytometry. Exercise resulted in a decrease ( P < 0.05) in the number and percentage of IFN-γ positive CD4+ and CD8+ T lymphocytes. These stimulated cells produced less IFN-γ immediately postexercise ( P < 0.05) and 2-h postexercise ( P < 0.05) compared with preexercise. However, CHO ingestion, which attenuated the exercise-induced stress hormone response compared with placebo ( P < 0.05), prevented both the decrease in the number and percentage of IFN-γ-positive CD4+ and CD8+ T lymphocytes and the suppression of IFN-γ production from stimulated CD4+ and CD8+ T lymphocytes. There was no effect of exercise on the number of, or cytokine production from, IL-4-positive CD4+ or CD8+ T lymphocytes. These data provide support for the role of exercise-induced elevations in stress hormones in the regulation of type 1 T lymphocyte cytokine production and distribution.

Objective. Lymphocytes are one of the main effector cells in the inflammatory response of acute pancreatitis (AP). The purpose of the study was to evaluate whether peripheral blood lymphocyte (PBL) subsets at admission change during AP based on clinical outcomes and to explore whether these changes vary by aetiology of AP. Hence, we performed a prospective study to find a predictor in lymphocyte subsets that might allow easier, earlier, and more accurate prediction of clinical outcomes. Methods. Patients with AP were enrolled from December 2017 to June 2018 at the First Affiliated Hospital of Nanjing Medical University. Age, sex, clinical and biochemical parameters, and aetiology of AP were obtained at admission. PBL counts were assessed within 24 hours after admission. Clinical outcomes were observed as endpoints. The areas under the curve (AUCs) of different predictors were calculated using the receiver operating characteristic (ROC) curve. Results. Overall, 133 patients were included. Patients (n=24) with organ failure (OF) had significantly lower CD4+ T lymphocyte levels than those (n=109) with No OF (NOF) (39.60 (33.94-46.13) vs. 32.41 (26.51-38.00), P=0.004). The OF group exhibited significantly higher CD19+ B lymphocytes than the NOF group (16.07 (10.67-21.06) vs. 23.78 (17.84-29.45), P=0.001). Of the AP cases, 68.8% were caused by gallstones; 10.1% were attributed to alcohol; 16.5% were due to hyperlipidaemia; and 4.6% had other causes. Across all aetiologies, a lower CD4+ T lymphocyte level was significantly related to OF (P<0.05). However, CD19+ B lymphocytes were significant only in gallstone pancreatitis (P<0.05). The ROC curve results showed that the AUC values of CD4+T lymphocytes, CD19+ B lymphocytes, and combined CD4+T lymphocytes and CD19+ B lymphocytes were similar to those of traditional scoring systems, such as APACHEII and Ranson. Conclusions. CD4+ T and CD19+ B lymphocytes during the early phase of AP can predict OF.

ABSTRACT Increased lymphocyte turnover is a hallmark of pathogenic lentiviral infection. To investigate perturbations in lymphocyte dynamics in natural hosts with nonpathogenic simian immunodeficiency virus (SIV) infection, the nucleoside analog bromodeoxyuridine (BrdU) was administered to six naturally SIV-infected and five SIV-negative sooty mangabeys. As a measure of lymphocyte turnover, we estimated the mean death rate by fitting a mathematical model to the fraction of BrdU-labeled cells during a 2-week labeling and a median 10-week delabeling period. Despite significantly lower total T- and B-lymphocyte counts in SIV-infected sooty mangabeys than in SIV-negative mangabeys, the turnover rate of B lymphocytes and CD4+ and CD8+ T lymphocytes was not increased in the SIV-infected animals. A small, rapidly proliferating CD45RA+ memory subset and a large, slower-proliferating CD45RA− central memory subset of CD4+ T lymphocytes identified in the peripheral blood of sooty mangabeys also did not show evidence of increased turnover in the context of SIV infection. Independently of SIV infection, the turnover of CD4+ T lymphocytes in sooty mangabeys was significantly higher (P < 0.01) than that of CD8+ T lymphocytes, a finding hitherto not reported in rhesus macaques or humans. The absence of aberrant T-lymphocyte turnover along with an inherently high rate of CD4+ T-lymphocyte turnover may help to preserve the pool of central memory CD4+ T lymphocytes in viremic SIV-infected sooty mangabeys and protect against progression to AIDS.

Clonal expansion of T lymphocytes in response to antigenic stimulation is a fundamental process of adaptive immunity. As a consequence of clonal expansion, some T lymphocytes acquire a senescent phenotype, fail to replicate in response to further antigenic stimulation, and express the killer cell lectin-like receptor G1 (KLRG1) and/or CD57. Physical exercise elicits a mobilization of large numbers of T lymphocytes into the bloodstream from peripheral lymphoid compartments, but the frequency of senescent cells in the mobilized population is not known. Eight male runners (age: 29 ± 9 yr; maximal O2 uptake 62 ± 6 ml·kg−1·min−1) performed an intensive treadmill-running protocol at 80% maximal O2 uptake to volitional exhaustion. Blood lymphocytes isolated before, immediately after, and 1 h after exercise were assessed for cell surface expression of KLRG1, CD57, CD28, CD45RA, CD45RO, CD62L, and lymphocyte subset markers (CD3, CD4, CD8, CD56) by flow cytometry. The percentage of all CD3+ T lymphocytes expressing KLRG1 and CD57 increased with exercise ( P < 0.01). The change in T-lymphocyte KLRG1 expression was attributed to both CD4+ and CD8 bright T cells, with the relative change being greater for the CD8 bright population ( P < 0.01). Mobilized T-lymphocyte populations expressing KLRG1 and CD57 appeared to extravasate the peripheral blood compartment after 1 h of recovery. In conclusion, T lymphocytes with a senescent phenotype are mobilized and subsequently removed from the bloodstream in response to acute high-intensity exercise. This suggests that T lymphocytes contained within the peripheral lymphoid compartments that are mobilized by exercise are likely to be at a more advanced stage of biological aging and have a reduced capacity for clonal expansion than blood-resident T cells.

La compréhension récente des mécanismes impliqués dans l’échappement tumoral au système immunitaire est fondamentale. En effet, cela a permis le développement de nouvelles immunothérapies à l’origine de réponses prolongées chez les patients atteints par plusieurs types de cancers. Cependant, une majorité de patients répondent insuffisamment ou rechutent. Il est donc indispensable d’identifier les mécanismes de résistances aux immunothérapies, et de nouvelles cibles permettant d’augmenter l’activité de ces thérapeutiques.La Neuropiline-1 (Nrp1) est une glycoprotéine transmembranaire indispensable à de nombreux processus physiologiques tels que l’angiogénèse et la guidance axonale. Nous avons montré dans le laboratoire qu’elle était exprimée dans le système immunitaire, lors de la synapse immunologique puis sur les cellules T conventionnelles activées.L’objectif de ce travail était d’étudier le rôle de la Nrp1 dans la réponse anti tumorale des lymphocytes T CD8+ chez la souris et chez l’homme.Nous avons montré que la délétion de Nrp1 sur les cellules T CD8+ murines augmente la réponse anti tumorale et diminue la croissance tumorale. Les cellules T CD8+ murines délétées pour la Nrp1 ont des capacités effectrices augmentées. La Nrp1 ne pouvant pas signaliser de manière autonome, nous avons montré qu’elle forme un complexe avec PD-1 chez la souris et chez l’homme et qu’elle en module son activité. Enfin, nous avons observé un effet synergique entre l’inhibition de Nrp1 et de PD1 chez la souris, ouvrant la possibilité d’une efficacité clinique chez les patients
T follicular helper (Tfh) cells play an essential role in the development of antigen-specific B cell immunity. Tfh cells regulate the differentiation and survival of activated B cells outside and inside germinal centers (GC) of secondary lymphoid organs. They act through cognate contacts with antigen-presenting B cells, but there is no current marker to specifically identify those Tfh cells which productively interact with B cells. Here we show that neuropilin 1 (Nrp1), a cell surface receptor, is selectively expressed by a subset of Tfh cells in human secondary lymphoid organs. Nrp1 expression on Tfh cells correlates with B cell differentiation in vivo and in vitro, is transient, and can be induced upon co-culture with autologous memory B cells in a cell contact-dependent manner. Comparative analysis of ex vivo Nrp1+ and Nrp1- Tfh cells reveals gene expression modulation during activation. Finally, Nrp1 is expressed by malignant Tfh-like cells in a severe case of angioimmunoblastic T-cell lymphoma (AITL) associated with elevated terminal B cell differentiation. Thus, Nrp1 is a specific marker of Tfh cells cognate activation in humans, which may prove useful as a prognostic factor and a therapeutic target in neoplastic diseases associated with Tfh cells activity

Historiquement, les LT CD8 cytotoxiques ont été considérés comme la seule composante cellulaire du système immunitaire nécessaire et suffisante pour l’élimination de cellules infectées par des virus ou transformées, les LT CD4 ne jouant qu’un rôle auxiliaire, dans le développement et le maintien de la réponse immune effectrice, ou modulateur par la fonction suppressive des T-Reg. Aux côtés, de ces fonctions auxiliaires ou suppressive, nombre de données indiquaient que les LT CD4 pouvaient également exercer une activité cytotoxique directe. Nos travaux ont permis par l’analyse chez l’Homme, de l’expression des récepteurs α à l’IL-2 (CD25) et à l’IL-7 (CD127) à la surface des LT CD4 du sang périphérique d’identifier une population singulière de LT CD4 caractérisée par l’absence de ces deux molécules. Ces LT CD4, CD25-CD127-, faiblement représentées chez les sujets sains, entre 0,2-2% des LT CD4 totaux du sang périphérique, étaient fortement augmentées, entre 2-20% dans les infections chroniques VIH et Tuberculose, et notamment dans les cancers incluant les mélanomes uvéaux métastatiques (Mum) et les cancers du sein. Puisque prédominant dans des situations de stimulation chronique, ces LT CD4 ont été définis comme des LT CD4 chroniquement stimulés : chCD4. Dans le sang périphérique de patients atteints de cancer comme chez les sujets sains, la majorité de ces chCD4 arboraient un phénotype mémoire/effecteur (CD45RO+). Cependant, dans les Mum et les cancers du sein la proportion de chCD4 effecteurs (CD45RO+CD27-) était fortement augmentée. Par ailleurs, si la plus part de ces cellules effectrices apparaissaient à un stade de différenciation terminale (CD57+), elles présentaient toutes les mêmes caractéristiques phénotypiques distinctes, définies par l’absence d’expression de la molécule de co-stimulation CD28 coordonnée à l’expression à leur surface de l’intégrine CD11b et du récepteur NK, 2B4. Dans les chCD4 effecteurs, nous avons également mis en évidence la présence spécifique de granules cytoplasmiques concentrant granzyme B et perforine, molécules impliquées dans la cytotoxicité directe de cellules cibles. Cette propriété fonctionnelle a été démontrée par des tests de cytotoxicité redirigée et était restreinte aux chCD4 effecteurs en comparaison aux autres sous-populations effectrices de LT CD4 conventionnels et T-Reg. L’analyse du profile de sécrétion de cytokines, révèle l’absence total de production d’IL-17 et un profile orienté Th1, soulevant la question du lignage de cette population particulière. L’absence d’expression de Ki67, marqueur des cellules en cycle, au sein de cette population de LT CD4 cytotoxiques, parallèlement à leur accumulation, suggérait qu’elles seraient capables de persister à l’état quiescent chez les patients. Par ailleurs, dans les Mum, nous avons mis en évidence que l’augmentation importante du nombre de chCD4 chez les patients, concordait avec la présence d’expansions oligoclonales au sien de cette population, et démontré une corrélation positive entre le pourcentage des cellules effectrices, chCD4 et LT CD8, LT CD8 parmi lesquels nous avons déterminé une fréquence élevée de cellules répondeuses spécifiques d’antigènes tumoraux associés à la tumeur. Nos travaux ont également permis d’évaluer l’impact de la chimiothérapie sur les populations lymphocytaires dans le sang périphérique. Chez les patientes atteintes de cancer du sein, traitées par chimiothérapie néo-adjuvante, c’est-à-dire préopératoire, nous avons constaté une augmentation du nombre de chCD4 chez 17/22 patientes. Nous avons mis en évidence que cette augmentation sous traitement était fortement corrélée au pourcentage de régression tumorale. L’ensemble de ces résultats apporte une nouvelle vision des LT CD4 dans l’immunité tumorale. (...)
Historically, CD8 positive Cytotoxic T Lymphocytes (CTL) have been associated with an effector immune response, while T cells with a CD4 phenotype where considered helper T cells. More recent data suggest that CD4 positive T cells are also capable of a direct cytotoxic activity. Through a systematic analysis of the IL-2 (CD25) as well as IL-7 (CD127) receptors α on the surface of CD4+ CTL in peripheral blood of patients before during and after treatment we were able to identify a specific CD4+ T cell population devoid of expression for these 2 molecules. These CD4+, CD25-CD127-, T cells only represent 0,2-2% of the total CD4+ pool in peripheral blood of healthy donors, while in the presence of a chronic infectious disease such as HIV or tuberculosis they were increased, representing up to 2-20% of all CD4+ T cells. Similarly, high numbers of CD4+, CD25-CD127-, T cells could be identified in the circulation in patients with metastatic uveal melanoma (muM) or with breast cancer. These chronically stimulated T cells (chCD4) demonstrate a memory effector phenotype (CD45RO+); while the majority shows a terminally differentiated phenotype (CD57+), these T cells all arbore distinct phenotypic characteristics as defined by the absence of expression of CD28 together with the presence of a surface expression of integrin CD11b and of the NK receptor, 2B4. The presence of cytoplasmic granules concentrating granzyme B and perforin, known to be responsible for T cell cytotoxicity, were identified in effector chCD4 while they were absent in conventional CD4+ T cells as well as in Tregs. This cytotoxic potential was demonstrated through redirected cytotoxicity assays that functionally confirm this feature of these chronically activated CD4+ T cells. The secretory cytokine profile showed absent IL-17 levels and a Th1 orientation, asking questions as regards to the lineage of this particular T cell population. Ki67 expression, a marker of cell proliferation, was absent, suggestive of their ability to persist quiescently in patients. However in muM patients we were able to demonstrate a vast oligoclonal increase in chCD4+ T cells, which correlated positively with CD8+ T cells. We were able to detect a high frequency of T cells responding against a specific tumor antigen among these CD8+ T cells. We furthermore studied the effects of chemotherapy on peripheral lymphocyte populations. In breast cancer patients who had been treated with preoperative (neoadjuvant) chemotherapy we detected high levels of effector chCD4 in 17/22 patients. Of particular interest was the fact that this increase through a course of chemotherapy treatment was strongly correlated to the percentage of regression of the original tumor. Together, these results cast new light on the role and function of CD4+ T cells in tumor immunity. Our observations show that CD4+ cytotoxic T lymphocytes do exist and suggest for the first time in human that they may have an important role in response to treatment and in particular in the establishment of a durable protective immune response

Les traitements par immunothérapie adoptive actuels sont compromis par une faible infiltration et expansion des LT CD8 injectés. Les travaux antérieurs de l'équipe ont montré une synergie entre les signaux du TCR et du récepteur à l'IL-2 pour la différenciation en Lymphocytes T (LT) effecteurs compétents, un effet qui peut être mimé par une forme constitutivement active du facteur de transcription STAT5 (STAT5CA). Mon projet de thèse à viser à exprimer ce STAT5 actif dans des LT CD8 anti-tumoraux dans le but d'augmenter leur réactivité. Nous démontrons que STAT5CA soutient l'expression de gènes contrôlant la migration, la survie, la composition des granules cytolytiques, la sécrétion de cytokines de type Tc1 (IFNy/TNFα) et leur potentiel de réponse secondaire. Les LT modifiés par STAT5CA sur-expriment les facteurs de transcription T-bet et Eomes qui sont associés respectivement à la différenciation en LT effecteur mémoire et central mémoire. Le potentiel cytolytique et migratoire des LT modifiés par STAT5CA rend ces cellules plus efficaces que des LT contrôlent pour induire une régression tumorale dans des modèles de mélanome transplanté ou induit (modèle TiRP). Ces résultats suggèrent une résistance accrue aux mécanismes d'immunosuppression intra-tumoraux. Contrairement aux LT contrôles, les LT modifiés par STAT5CA sous-expriment l'IL-6Rα et le TGFβRII et ont une moindre sensibilité à l'action immunosuppressive des cytokines IL-6 et TGFβ1
Adoptive therapies are compromised by poor infiltration and expansion of injected CD8 T cells. Previous work in our team has demonstrated that signals from TCR and IL-2 receptor are acting in synergy to promote the differentiation of CD8 T cells. Moreover, this IL-2 effect can be mimicked by a constitutive active form of STAT5 (STAT5CA). During my PhD, I expressed this active STAT5 in anti-tumor CD8 T cells in order to enhance their activity. We demonstrated that STAT5CA sustains gene expression involved in migration, survival, cytolytic granules composition, Tc1 cytokine secretion (IFNy/TNFα) and secondary response potential. T cells transduced with STAT5CA up-regulate expression of the transcription factors T-bet and Eomes which are involved respectively in effector or central memory T cell differentiation. Cytolytic and migratory properties of STAT5CA T cells contribute to their capacities to induce regression of both transplanted and induced (TiRP model) melanomas, while control T cells were inefficient. Those results suggest that STAT5CA T cells are less sensitive to tumor-derived immunosuppression. Compared to control T cells, STAT5CA T cells show a down-regulation of IL-6Rα and TGFβRII which correlate with their decreased sensitivity to IL-6 and TGF1 derived immunosuppression. Moreover, STAT5CA T cells infiltrate lung, liver and pancreas which open possible treatments for highly frequent tumors that are not efficiently cured

Les lymphocytes T (LT) CD8 innés sont une population de LT non conventionnels récemment décrits dans le laboratoire. On les qualifie de « non conventionnels » car ils possèdent des caractéristiques de l’immunité acquise (facteur de transcription Eomesodermine et phénotype T mémoire) mais aussi de l’immunité innée (récepteurs des cellules NK, réponse à une stimulation cytokinique de type inné). Les fonctions de ces cellules sont encore peu connues, même s’il existe un faisceau d’argument en faveur de leur implication dans l’immunité anti-infectieuse et anti-tumorale.Il a été décrit que l’immuno-sénescence et/ou la stimulation antigénique chronique (induite par exemple par les infections virales chroniques au cytomégalovirus ou CMV) entraîne(nt) l’expression de marqueurs NK par les LT. Ce phénotype se rapproche donc de celui de nos cellules d’intérêt. Pour étudier l’effet de la stimulation antigénique chronique sur le compartiment LT CD8, et spécialement sa composante innée, nous avons choisi comme modèle la transplantation d’organe. Dans ce domaine, la recherche s’intéresse aux populations immunitaires susceptibles de jouer un rôle dans la tolérance ou le rejet du greffon. Parmi elles, les LT CD8 innés méritent une attention spéciale, ceci du fait de leurs fonctions innées effectrices/cytotoxiques. Nous avons présumé leur (re)programmation par la stimulation antigénique chronique (du greffon et/ou virale) pendant la transplantation. Cette hypothèse a été testée à partir d’une cohorte de patients transplantés rénaux depuis plus de dix ans, sous traitement immunosuppresseur minimisé (ciclosporine A (CsA) en monothérapie), en l’absence de signe clinico-biologique de rejet. Notre travail a d’abord permis de révéler dans les LT CD8 innés issus des donneurs sains (DS) un phénotype sénescent accentué (fréquence de cellules CD27(-)CD28(-) augmentée) que les LT CD8 conventionnels. En outre, la fréquence de cette population T innée, contrairement aux LT CD8 conventionnels, ne corrélait pas avec l’âge. Dans la cohorte de patients transplantés, nous avons observé une augmentation de la fréquence des LT CD8 innés, accompagnée d’un phénotype sénescent et effecteur terminal (CD45RA(+)CCR7(-)) exacerbé, comparativement aux cellules des DS. Les patients présentant une sérologie positive pour le CMV avaient un phénotype sénescent accru par rapport aux patients présentant une sérologie négative.En altérant la signalisation du TCR, le traitement immunosuppresseur CsA pourrait faciliter la (re)programmation des LT CD8 en faveur de leur versant inné. En accord avec cette hypothèse, une modélisation in vitro des effets de la CsA sur les LT CD8 provenant de DS en présence d’une stimulation du TCR et d’IL-15 a permis de documenter une augmentation du pool de LT CD8 innés au détriment du pool de LT naïfs, laquelle est accompagnée d’une valorisation de leurs fonctions (production innée d’IFN-γ). A l’inverse, chez les patients, les LT CD8 innés étaient dysfonctionnels, avec une production innée d’IFN-γ diminuée qui pourrait résulter de leur expression membranaire diminuée du récepteur de l’IL-15, cytokine indispensable aux LT CD8 innés. Ce dysfonctionnement, qui ne peut être attribué à un programme d’exhaustion ni être relié à un antécédent de cancer, pose la question du rôle de la stimulation allo-spécifique chronique. De façon générale, ce travail suggère que le contexte d’allogreffe rénale entraîne une reprogrammation et un phénotype de type « vieillissement » des LT CD8 innés, liés au moins en partie au traitement immunosuppresseur. Cette hypothèse devra être confortée par une analyse fine de l’allo-spécificité des LT CD8 innés dirigée contre le greffon
Innate CD8 T-cells are a non-conventional αβ-T-cell population recently described in our laboratory. We call them “non-conventional” because of their expression of markers from both adaptive immunity (transcription factor Eomesodermin and memory T-cell phenotype) and innate immunity (Natural Killer cell receptors, response to innate-like cytokine stimulation). The functions of innate CD8 T-cells are not well-known, although there are strong arguments for their involvement in anti-infectious and anti-tumor immunity.It has been reported that immunosenescence and/or chronic antigenic stimulation (induced, for example, by chronic viral cytomegalovirus (CMV) infections) result(s) in NK marker expression by T-cells. This phenotype is therefore similar to that of our cells of interest. To study the influence of chronic antigen stimulation on CD8 T-cells, and especially their innate component, we chose organ transplantation as a model. In this domain, research has been focused on immune cell populations that may play a role in graft tolerance or rejection. Among them, innate CD8 T-cells deserve special attention due to their effector/cytotoxic innate functions. We presumed their being reprogrammed by graft and/or viral chronic stimulation during organ transplantation. This hypothesis was tested in a cohort of patients with kidney-transplants for more than ten years, under minimized immunosuppressive treatment (ciclosporin A (CsA) monotherapy), without any clinical and biological sign of rejection. First, our work revealed a more accentuated senescent phenotype (increased frequency of CD27(-)CD28(-) cells) in innate CD8 T-cells from healthy donors (HD) than in their conventional counterpart. Moreover, the frequency of the innate T-cell population, unlike that of conventional CD8 T-cells, did not correlate with age.In the cohort of transplant patients, we observed an increased frequency of innate CD8 T-cells, accompanied by an exacerbated senescent and terminal effector (CD45RA(+)CCR7(-)) phenotype, compared to HD cells. Patients with positive CMV serology had an increased senescent phenotype compared to patients with negative serology.By altering TCR signaling, CsA immunosuppressive therapy could also facilitate the (re)programming of CD8 T-cells in favor of their innate counterpart. In agreement with this hypothesis, in vitro modeling of CsA effects on CD8 T-cells from HD in the presence of IL-15 and TCR stimulation enabled us to document an increased innate CD8 T-cell pool to the detriment of the naive CD8 T-cell pool, accompanied by an enhancement of their functions (innate production of IFN-γ).Conversely, in transplant patients, innate CD8 T-cells were dysfunctional, with decreased innate IFN-γ production, which may result from their decreased membrane expression of the IL-15 receptor, a cytokine essential for innate CD8 T-cells. This dysfunction, which cannot be attributed to cellular exhaustion or cancer history, raises the question of the role of chronic allo-specific stimulation.All in all, this work suggests that the context of renal allogenic transplantation leads to reprogramming and aging-like phenotype of innate CD8 T-cells, linked (at least partially) to immunosuppressive treatment. This hypothesis requires confirmation by a precise analysis of the direct allo-specificity of innate CD8 T-cells against the graft

Chez la plupart des primates adultes, les lymphocytes T (LT) γ9δ2, représentant la majorité des LTγδ périphériques, jouent un rôle important dans la protection de l'organisme (ex. Agents infectieux, tumeurs). Des molécules activant spécifiquement les LTγ9δ2 ont été caractérisées et sont majoritairement des composés non-peptidiques phosphorylés appelés phosphoantigènes (PAg). Les PAg naturels correspondent à des métabolites de voies de synthèse des isoprénoïdes proches aux cellules procaryotes et eucaryotes. Les modalités d'activation des LTγ9δ2 induite par les PAg demeurent mal connues. Des données obtenues dans l'équipe ont révélé le rôle clé joué par la glycoprotéine BTN3A (butyrophyline, CD277), et en particulier de l'isoforme BTN3A1, dans l'activation antigénique des LTγ9δ2 induite par les PAg. Mes travaux ont visé à étudier les mécanismes impliquant BTN3A lors de l'activation des LTγ9δ2. J'ai ainsi pu montrer que le domaine intracellulaire B30. 2 de BTN3A1 peut interagir avec les PAg, notamment grâce à l'histidine 351, constituant majeur et exclusif d'une poche chargée de ce domaine. En parallèle, j'ai mis en évidence l'implication d'autres protéines pouvant interagir avec ce domaine intracellulaire, par utilisation de la technique du double-hybride. Ces travaux ont révélé l'existence de six protéines candidates partenaires de BTN3A. Enfin, mes résultats ont permis de proposer une cartographie fonctionnelle de l'intégralité des isoformes de BTN3A. L'ensemble de mes travaux a permis d'apporter un éclairage nouveau sur les modalités fines d'activation antigénique des LTγ9δ2 induite par les PAg et de préciser le rôle clé joué par les molécules BTN3A dans ce processus
Vγ9Vδ2 T cells are the major sub-population of γδ T cells in human blood. They play a leading part in protection of the organism against infectious agents and tumor cells. Vγ9Vδ2 T cells are specifically and strongly activated by small organic pyrophosphate molecules termed phosphoantigens (PAg) in a TCR dependant way. PAg are metabolites from the isoprenoid pathway shared by both procaryotes and eucaryotes. The activation modalities of Vγ9Vδ2 T cells by PAg remain to be defined in detail. Results from our team revealed an important role played by the BTN3 (CD277) molecule during Vγ9Vδ2 T cell antigenic activation. BTN3, and especially the BTN3A1 isoform, is involved in activating Vγ9Vδ2 T cells. The work described in this thesis, aimed at investigating the underlying mechnisms allowing BTN3 molecule to activate Vγ9Vδ2 T cells. We showed that the B30. 2 intracellular domain of BTN3A1 was able to fix PAg with a histidine residue in position 351 playing a vital role. Furthermore, we identified other proteins that could interact with this intracellular domain. We used the yeast double-hybrid technique, and identified six putative partner proteins. Finally, we carried out a function maping of the intracellular part of the various BTN3 isoforms. These results brought new insights into the antigenic activation modalities of Vγ9Vδ2 T cells by PAg and clarify the key role played by the BTN3 molecule in this process

Les lymphocytes cytotoxiques T CD8+ (LT CD8+) sont des cellules de l'immunité adaptative qui jouent un rôle majeur dans les réponses immunitaires antitumorales puisqu'ils reconnaissent et tuent spécifiquement les cellules cancéreuses. Cependant, leurs fonctions antitumorales sont souvent limitées par l'expression de récepteurs inhibiteurs tels que CTLA-4 et PD-1. Bien que les immunothérapies basées sur le blocage de ces récepteurs représentent l'une des avancées majeures dans le traitement du cancer, de nombreux cancers y sont réfractaires. Ainsi, il est aujourd'hui nécessaire de comprendre davantage les mécanismes à l'origine de cette résistance thérapeutique et d'identifier d'autres cibles régulant les fonctions antitumorales des LT CD8+. Tandis que les stratégies immunothérapeutiques actuelles se concentrent essentiellement sur l'identification d'autres récepteurs inhibiteurs, le rôle des récepteurs activateurs des LT CD8+ dans la réponse aux immunothérapies reste encore peu approfondi. Initialement décrite comme une molécule d'adhésion, CD226 (DNAM-1) est un récepteur coactivateur exprimé par les cellules NK et les LT CD8+ qui stimule leur production de cytokines inflammatoires et de granules cytolytiques vis-à-vis de cellules cibles suite à son interaction avec ses ligands CD112 et CD155. La nectine CD112 et la "nectine-like" CD155 sont fréquemment exprimées par les cellules tumorales et des modèles murins immunodéficients CD226-/- ont pu démontrer que CD226 joue rôle critique dans l'immunosurveillance antitumorale. Par ailleurs, les récepteurs inhibiteurs TIGIT et CD96 qui rentrent en compétition avec CD226 ont récemment été caractérisés comme des cibles d'immunothérapies intéressantes, ce qui renforce l'idée selon laquelle la réponse immunitaire antitumorale est régulée par CD226. Au cours de ma thèse, j'ai mis en évidence que CD226 identifie les populations LT CD8+ CD226- et LT CD226+ chez des individus sains et des patients atteints de cancer. Des analyses transcriptomiques et fonctionnelles m'ont permis de démontrer que l'absence de CD226 conduit à une altération majeure de la prolifération et des fonctions effectrices des LT CD8+ stimulés par le TCR. Mes analyses effectuées sur des LT CD8+ infiltrant la tumeur chez des patients atteints de cancer et chez des souris porteuses de tumeur m'ont conduit à observer que le développement tumoral favorise l'accumulation des LT CD8+ CD226- hyporépondeurs au TCR au site de la tumeur.[...]
CD8+ cytotoxic T lymphocytes (CTL) are key immune cells that play an important role in the control of tumor development through their ability of killing cancer cells. However, cancer cells can frequently escape CD8 T-cell recognition and cytolytic functions through the engagement of inhibitory receptors such as CTLA-4 and PD-1. Although immune checkpoint blockade (ICB) such as monoclonal antibody (mAb) anti-PD-1 has represented a promising cancer therapy in cancer care, clinical responses are not observed in the majority of cancer patients. Therefore, elucidating the mechanisms of this lack of responsiveness and finding additional signals that regulate CD8+ T cell anti-tumor functions has become a major priority. While most of the experimental strategy mainly focus on the identification of additional inhibitory receptors, the importance of coactivating receptors in the antitumor CD8+ T cell functions and ICB efficacy remains to be better investigated. Initially described as an adhesion molecule, CD226 (DNAM-1) is co-activating receptor expressed by NK cells and CD8+ T cells that stimulate the secretion of pro-inflammatory cytokines and release of cytolytic granules towards target cells. Its ligands, the nectin and nectin-like receptors CD112 and CD155, are often expressed on cancer cells and CD226 was shown to play a critical role in immunosurveillance in numerous tumor mouse models. The inhibitory receptors TIGIT and CD96 that compete with CD226 were recently identified as promising immunotherapeutic targets to restore CD8+ T cell reactivity against cancer, thus highlighting the importance of CD226 axis in the regulation of anti-tumor immune responses. During my PhD, I found that CD226 identifies CD226- CD8+ and CD226+ CD8+ T cells populations in healthy donors and in cancers patients. Through transcriptomic, molecular and functional analysis, I found that the CD226 absence alters CD8+ T cell responsiveness to TCR stimulation. Unlike CD226+ CD8+ T cells, CD226- CD8+ T cells have deeply intrinsic functional abnormalities such as poor proliferation, cytokines production and cytotoxic functions upon TCR stimulation. Using complementary set of experiments involving human samples and mouse tumors models, I observed that tumor development favors the accumulation of tumor-infiltrating CD226- CD8+ T lymphocytes (TILs) through an Eomes-dependent mechanism.[...]

Le cytomégalovirus est une cause infectieuse majeure de morbi-mortalité après une transplantation rénale. Une meilleure connaissance des acteurs du système immunitaire impliqués dans la réponse contre le CMV et de l'effet des médicaments immunosuppresseurs sur ces acteurs permettrait d'améliorer la prise en charge des patients. Nous avons précédemment démontré que les lymphocytes T γδ (LTγδ) (et plus particulièrement les populations n'exprimant pas la chaine Vδ2 du TCR) avaient des caractéristiques de cellules adaptatives et étaient des cellules effectrices clés répondant au CMV et associées à la guérison. Dans un premier temps, nous avons analysé le répertoire et les fonctions des lymphocytes T γδ Vδ2neg naïves pour mieux connaître leurs propriétés "innées" grâce à une analyse transcriptomique à l'échelle de la cellule (single cell RNASeq). Deuxièmement, un sous-groupe de LTγδ, les Vγ9negVδ2pos ayant également des caractéristiques adaptatives a été récemment décrit chez l'adulte. Nous avons montré que ces LTγδ Vγ9negVδ2pos sont également des composants de la réponse immunitaire contre le CMV tout en présentant des caractéristiques distinctes de celles des LTγδ Vδ2neg. Notamment, les LTγδ Vγ9negVδ2pos étaient le seul sous-groupe de LTγδ dont l'expansion était corrélée à la gravité de la maladie à CMV. Par conséquent, ce travail évalue un nouvel acteur dans la réponse immunitaire contre le CMV et ouvre des perspectives cliniques intéressantes pour l'utilisation des LTγδ Vγ9negVδ2pos comme immuno-marqueur de la gravité de la maladie à CMV.Enfin, nous avons analysé l'effet des inhibiteurs mTOR (mTORi), traitement anti-rejet utilisé en transplantation rénale, sur les lymphocytes T spécifiques du CMV. En effet, les mTORi sont associés à une moindre incidence d'infection à CMV chez les receveurs séropositifs (R+) de greffes de rein (KTR) mais leur impact sur la réponse T n'est pas connu. Nous avons émis l'hypothèse que la réactivation du CMV chez les patients R+ pourrait être due à une dysfonction des lymphocytes T qui pourrait être améliorée par les mTORi. Nous avons d'abord montré que les lymphocytes T alpha-bêta et gamma-delta présentaient un phénotype plus dysfonctionnel (LAG3+, TIM3+, PD-1+, CD85j+) à la transplantation chez les 16 R+ KTR chez qui survenait une réactivation sévère du CMV par rapport aux 17 patients sans reactivation ou avec une infection spontanément résolutive. Les patients sous mTORi (n=27) avaient une proportion diminuée de lymphocytes T alpha-beta et gamma-delta PD-1+ et CD85j+ par rapport aux patients traités par acide mycophénolique (MPA) (n=44), ce qui était corrélé avec une fréquence et une gravité moindre des infections à CMV. Les patients sous mTORi présentaient également des proportions plus élevées de lymphocytes T cytotoxiques. In vitro, les mTORi augmentaient la prolifération, la survie et la production d'interferon-gamma contre le CMV par les lymphocytes T alpha-beta et gamma-delta. Les proportions de cellules PD-1+ et CD85j+ étaient également diminuées sous mTORi dans les deux sous-populations et leur profil majoritaire devenait "EOMES low/ Hobit high". Dans les lymphocytes T gamma-delta, l'effet des mTORi était lié à une augmentation de la signalisation TCR. Ces résultats révèlent (i) qu'une réplication sévère du CMV est associée à un profil dysfonctionnel des lymphocytes T et (ii) que les mTORi améliorent leur aptitude de façon associée au meilleur contrôle du CMV. Le phénotype de lymphocytes T dysfonctionnel pourrait représenter un nouvel immuno-marqueur chez les patients R+ pour prédire l'infection post-transplantation et aider à stratifier les patients qui devraient bénéficier du traitement mTORi
Cytomegalovirus is a major infectious cause of mortality and morbidity following transplantation and a better knowledge about the immune cells acting against CMV and about their response to immunosuppressive drugs would help to better manage this life threatening infection. We have previously demonstrated that the tissue-associated adaptive Vδ2neg γδ T-cells are key effectors responding to CMV and associated to recovery. We analyzed here the repertoire and functions of naive Vδ2neg γδ T-cells to know better their "innate" properties against CMV. Secondly, an additional Vγ9negVδ2pos subgroup with adaptive functions has been recently described in adults. We demonstrated that these Vγ9negVδ2pos T-cells are also components of the CMV immune response while presenting with distinct characteristics from Vδ2neg γδT-cells. Notably Vγ9negVδ2pos T-cells were the only γδ T-cell subset which expansion tightly correlated with the severity of CMV disease. Consequently, we identified a new player in the immune response against CMV and open interesting clinical perspectives for using Vγ9negVδ2pos T-cells as an immune marker for CMV disease severity in immunocompromised patients.Finally, we analyzed the effect of mTOR-inhibitors (mTORi), immunosuppressive drugs, on CMV-specific T cells. Indeed, mTORi are inexplicably associated with a lower incidence of CMV infection in seropositive (R+) kidney transplant recipients (KTR). We hypothesized that CMV reactivation in R+ patients could be due to dysfunctional T cells that might be improved by mTORi. First we showed that both alpha-beta and gamma-delta T cells displayed a more dysfunctional phenotype (LAG3+, TIM3+, PD-1+, CD85j+) at day 0 in the 16 R+ KTR with severe CMV reactivation when compared to the 17 with spontaneously resolving or without CMV reactivation. Second, treating patients with mTORi (n= 27) decreased the proportion of PD-1+ and CD85j+ alpha-beta and gamma-delta T cells when compared to mycophenolic acid (MPA) treated patients (n=44), which correlate with the frequency and severity of CMV infections. mTORi-treated patients also lead to higher proportions of late-differentiated and cytotoxic gamma-delta T cells and increased percentages of IFN-gamma producing and cytotoxic alpha-beta T cells. In vitro, mTORi increased proliferation, survival and CMV-induced IFN-gamma-production of alpha-beta and gamma-delta T cells. mTORi also decreased PD-1 and CD85j expression in both subsets and shifted to a more efficient EOMESlow Hobit high profile. In gamma-delta T cells mTORi effect was related to increased TCR signaling. Those results reveal (i) that severe CMV replication is associated with a dysfunctional T cell profile and (ii) that mTORi improve their fitness in association with a better control of CMV. Dysfunctional T cell phenotype could represent a new biomarker in R+ patients to predict post-transplantation infection and help to stratify patients who should benefit from mTORi treatment

DQ2 is a surface receptor of class II MHC exposed on APC immune-competent cells. Its function is to recognize non-self-antigens and present them to CD4+ T-helper lymphocytes, which activate cytokine <21> production and control antibody production and cell response. The activation of T lymphocytes by peptides derived from gluten proteins and the production of antibodies directed against tTG in tissues where it is localized is the basis of the etiopathogenesis of celiac disease (CD). CD is frequently associated with the presence of specific HLA system genes encoding heterodimers DQ2 and DQ8, identifiable by the DQA1*0501/DQB1*0201 or DQA1*0501/DQB1*0202 and DQB1*0302 alleles. DQ2 is also associated with genetic, endocrinological and neurological diseases such as: type 1 diabetes, thyroiditis, pancreatitis and multiple sclerosis. Interactions between DQ2 and T lymphoma have also been demonstrated. The correlation between autoimmune diseases in patients with CD and therefore DQ2 is much more frequent than in healthy subjects.

White cells (leucocytes) mediate inflammatory and immune responses and are key to the defence of the host against microbial pathogens. Subpopulations of leucocytes include granulocytes—neutrophils, eosinophils, and basophils; monocytes; and lymphocytes. Neutrophils comprise half the peripheral circulating leucocytes and are characterized by heterogeneous primary and secondary granules and a segmented nucleus. Maturation from the haematopoietic stem cell occurs in the bone marrow and takes 10 to 14 days. Neutrophilia—defined as an increase in the circulating neutrophil count to greater than 7.5 × 10⁶/µl, usually occurs as an acquired reactive response to underlying disease. Causes include infection, particularly bacterial; drugs; malignancies, and hereditary conditions. Neutropenia—defined as a reduction in the absolute neutrophil count to less than 1.5 × 10⁶/µl, is of particular importance because, when severe (<0.5 × 10⁶/µl), it markedly increases the risk of life-threatening infection. Causes include drugs and toxins, postinfectious, nutritional deficiencies, autoimmune, large granular lymphocytosis, and congenital. Disorders of neutrophil function include chronic granulomatous disease, leucocyte adhesion deficiency, myeloperoxidase deficiency, and Chediak–Higashi syndrome. Monocytes share a common myeloid precursor with granulocytes, present antigens to T cells, produce several important cytokines with immunomodulatory and inflammatory functions, and are the precursors to resident tissue macrophages. They are especially important in defence against intracellular pathogens. Causes of monocytosis (>0.9 × 10⁶/µl) include chronic infection, autoimmune diseases, and malignancy. Basophils are nonphagocytic granulocytes that function in immediate-type hypersensitivity. Basophilia (> 0.2 × 10⁶/µl) is seen in myeloproliferative disorders, hypersensitivity reactions, and with some viral infections.

Plasminogen activators (PA) are thought to play a role in the invasive and metastatic properties of many types of cancer cells. Though, discrepancies in correlations between fibrinolytic activity and metastatic potential of malignant cells have been described.In this study, we evaluated both tissue type (tPA) and urokinase type (UK) cellular PA activities in different mononuclear cell types : normal T and B human peripheral lymphocytes, B cells from patients with chronic lymphocytic leukemia (CLL), human blood monocytes, alveolar macrophages, U 937, RAJI and JM cell 1ines.Mononuclear cells were isolated by Ficoll-hypaque gradients and monocytes by plastic adhesion. T and B cells were separated by a rosetting technique using sheep red blood cells. Cellular extracts were prepared by 0.5 % Triton X 100 buffer treatment followed by sonication and centrifugation 10 ' at 2000 g. PA assays were performed on the supernatants.UK-type PA was evaluated by a liquid-phase assay in presence of human plasminogen (Kabi) and chromogenic substrate S 2251 (Kabi).tPA was determinated using a solid-phase fibrin activity assay which involves an affinity separation step and thus allows selective detection of tPA.In both cases, results were reported in international units by reference to standard curves of UK (Choay) or tPA (Kabi).In all cell types tested, PA detected was essentially urokinase-type. Highest PA activity was found in U 937 cells (0.7 IU/5×l06 cells). In normal blood lymphocytes, mean PA activity was 0.08 IU/5×l06 cells. Examination of lymphocytes from patients with CLL revealed a marked decrease in UK activity as compared to normals (< 0.01 IU/5×106 cells in more than 50 % cases).The function of PA in normal lymphocyte physiology and the potential pathogenic role of diminished PA in CLL lymphocytes remains to be investigated.