Objective This study aimed to analyze the characteristics and clinical significance of peripheral lymphocytic subsets and cytokine levels, including interleukin 1β(IL-1β), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12P70, IL-17A, tumor necrosis factor α(TNF-α), interferon γ(IFN-γ) and IFN-α, in patients with primary biliary cholangitis (PBC), to provide some novel insights into the pathogenesis of PBC. Methods We retrospectively collected clinical features and laboratory data from hospitalized patients who were primarily diagnosed with PBC and from healthy physical examinees at the Third People's Hospital of Changzhou between January 1, 2023, and June 30, 2024. Results A total of 152 PBC patients and 96 healthy controls who met the inclusion and exclusion criteria were enrolled. Significant differences were observed in baseline characteristics and laboratory data between the two groups. After the propensity score matching (PSM) analysis, 61 PBC patients and 61 healthy controls were successfully matched, ensuring that the general characteristics (age and gender) of the two groups were balanced and comparable. Compared to the control group, the proportion of peripheral lymphocytes was significantly higher in the PBC group (31.9% vs. 17.8%), primarily due to an increase in CD4⁺ T cells (46.77% vs. 41.19%), while CD8⁺T cells were significantly decreased (19.73% vs. 22.07%). Notably, the proportions of CD4⁺ programmed cell death 1 (PD-1)⁺ T and CD8⁺PD-1⁺ T cells were elevated, with CD8⁺PD-1⁺ T cells showing a significant positive correlation with the severity of liver inflammation (r=0.41). Furthermore, the mitochondrial mass (MM) of CD4⁺ T cells was significantly increased in PBC patients, whereas no significant changes were observed in the MM of CD8⁺ T cells or the mitochondrial membrane potential (MMP) of CD3⁺ T cells. Additionally, the plasma levels of cytokines, such as IL-4, IL-8, IL-10 and IFN-α, were abnormally elevated. The plasma levels of IL-5 and IL-1β were negatively correlated with the stage of liver fibrosis in patients with PBC (r=-0.52). Conclusion The overactivation and proliferation of CD4⁺ T cells, along with the suppression of CD8⁺ T cell function and increased PD-1 expression leads to T cell exhaustion, indicating significant immunological alterations in PBC patients. These changes are closely associated with the disease progression. Additionally, cytokines are likely involved in the immune regulation process of PBC and may influence the pathogenic mechanisms of the disease. Regular monitoring of lymphocyte subsets and cytokine levels can help assess the immune status and disease activity in patients with PBC, thereby guiding the individualized treatment strategies.
Humans ; Male ; Female ; Middle Aged ; Liver Cirrhosis, Biliary/blood* ; Retrospective Studies ; T-Lymphocyte Subsets/immunology* ; Aged ; Cytokines/blood* ; Adult ; CD8-Positive T-Lymphocytes/immunology*

Objective To investigate the relationship between serum platelet-activating factor (PAF) level, T cell immune function and disease activity in vitiligo patients. Methods A total of 102 patients with vitiligo treated in our hospital from July 18th, 2022 to July 26th, 2023 were enrolled as study subjects. According to VIDA score, the patients were divided into an advanced-stage group (n=54) and a stable stage group (n=49). PAF and T lymphocyte levels were compared between the two groups. Logistic regression analysis was performed to examine the relationship between PAF levels and disease activity, as well as their correlation with T cell subsets. Unconditional logistic regression modeling was employed to analyze the interaction between PAF levels and T cell subsets in disease activity. Results No significant difference was observed in CD3⁺ levels between advanced and stable stage vitiligo patients. PAF and CD8⁺ levels in advanced group were significantly higher than those in stable group, while CD4⁺ levles and CD4⁺/CD8⁺ ratios were significantly lower than those in stable group. When PAF level was 18.24 ng/L, the maximum Youden index reached 0.670, with corresponding sensitivity of 84.22% and specificity of 82.77%. The area under ROC curve AUC was 0.858. The intensity of association between PAF level and disease activity was nonlinear dose-response relationship. Among patients with VIDA score ≥1, significant differences were observed in both CD4⁺ and CD8⁺ levels across different PAF levels, and the CD4⁺/CD8⁺ ratios in vitiligo patients with different VIDA scores was significantly different. Interaction analysis revealed that after adjusting for confounding factors, the effect of PAF levels and T cell subsets on disease activity in vitiligo patients showed significant interaction in both additive model (RERI=4.674, 95%CI: 1.032~11.942; AP=0.763, 95%CI: 0.336~1.201; S=6.854, 95%CI: 1.904~16.520) and multiplicative model (OR=3.461, 95%CI: 1.365~8.713). Conclusion Serum PAF, CD4⁺, CD8⁺ and CD4⁺/CD8⁺ of vitiligo patients are closely related to disease activity, and PAF level interacts with T cell subsets (CD4⁺, CD8⁺, CD4⁺/CD8⁺) in the disease activity of vitiligo patients. PAF and T cell immune function may contribute to the occurrence and development of vitiligo, which could serve as clinical indicators of disease activity to guide timely management.
Humans ; Vitiligo/blood* ; Platelet Activating Factor/immunology* ; Male ; Female ; Adult ; Middle Aged ; Young Adult ; T-Lymphocytes/immunology* ; Adolescent ; T-Lymphocyte Subsets/immunology*

OBJECTIVE: To analyze the correlation between the expression levels of Tim-3, C-myc and the proportion of T lymphocyte subsets and prognosis in patients with acute lymphoblastic leukemia (ALL). METHODS: The research group selected 60 ALL patients admitted to our hospital from December 2019 to December 2021, while the control group selected 55 healthy volunteers who underwent physical examination in our hospital. The expression levels of Tim-3, C-myc mRNA and the proportion of T lymphocyte subsets in the two groups were detected. The mortality rate of ALL patients was calculated, and the correlation between the expression levels of Tim-3, C-myc, and the proportion of T lymphocyte subsets and pathological features and prognosis was analyzed. RESULTS: Compared with the control group, the levels of Tim-3, C-myc and CD8⁺ in the research group were increased, while the levels of CD3⁺ , CD4⁺ and CD4⁺ /CD8⁺ were decreased (all P < 0.001). The levels of Tim-3, C-myc mRNA, CD3⁺ , CD4⁺ , CD8⁺ , CD4⁺ /CD8⁺ were correlated with risk classification and extramedullary infiltration (all P < 0.05). The survival rate of patients with low expression of Tim-3, C-myc, and CD8⁺ was higher than that of patients with high expression, while the survival rate of patients with high expression of CD3⁺ , CD4⁺ , and CD4⁺ /CD8⁺ was higher than that of patients with low expression (all P < 0.05). Univariate analysis showed that the deceased patients had higher proportions of extramedullary infiltration and high-risk classification, as well as higher levels of Tim-3, C-myc, and CD8⁺ , while lower levels of CD3⁺ , CD4⁺ , and CD4⁺ /CD8⁺ compared with surviving patients (all P < 0.01). Multivariate logistic regression analysis showed that extramedullary invasion, risk classification, Tim-3, C-myc, CD3⁺ , CD4⁺ , CD8⁺ , CD4⁺ /CD8⁺ were the main factors affecting the prognosis of ALL patients (all P < 0.05). ROC curve analysis showed that the combination of Tim-3, C-myc, and T lymphocyte subsets had higher sensitivity and accuracy in predicting prognosis of ALL patients compared with the single diagnosis of Tim-3, C-myc, CD3⁺ , CD4⁺ , CD8⁺ , and CD4⁺ /CD8⁺ (P < 0.05). CONCLUSION ALL patients show higher levels of Tim-3, C-myc mRNA and CD8⁺ but lower levels of CD3⁺ , CD4⁺ and CD4⁺/CD8⁺. Moreover, the expression levels of Tim-3, C-myc, CD3⁺ , CD4⁺ , CD8⁺ and CD4⁺/CD8⁺ are correlated with extramedullary invasion, high-risk classification and prognosis.
Humans ; Hepatitis A Virus Cellular Receptor 2/metabolism* ; Prognosis ; Proto-Oncogene Proteins c-myc/metabolism* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis* ; T-Lymphocyte Subsets ; Male ; Female ; Adult ; Middle Aged ; Adolescent ; RNA, Messenger

OBJECTIVE: To analyze the Epstein-Barr virus (EBV) load in different lymphocyte subsets, as well as clinical characteristics and outcomes in patients with hematologic malignancies experiencing EBV reactivation. METHODS: Peripheral blood samples from patients were collected. B, T, and NK cells were isolated sorting with magnetic beads by flow cytometry. The EBV load in each subset was quantitated by real-time quantitative polymerase chain reaction (RT-qPCR). Clinical data were colleted from electronic medical records. Survival status was followed up through outpatient visits and telephone calls. Statistical analyses were performed using SPSS 25.0. RESULTS: A total of 39 patients with hematologic malignancies were included, among whom 35 patients had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). The median time to EBV reactivation was 4.8 months (range: 1.7-57.1 months) after allo-HSCT. EBV was detected in B, T, and NK cells in 20 patients, in B and T cells in 11 patients, and only in B cells in 4 patients. In the 35 patients, the median EBV load in B cells was 2.19×10⁴ copies/ml, significantly higher than that in T cells (4.00×10³ copies/ml, P <0.01) and NK cells (2.85×10² copies/ml, P <0.01). Rituximab (RTX) was administered for 32 patients, resulting in EBV negativity in 32 patients with a median time of 8 days (range: 2-39 days). Post-treatment analysis of 13 patients showed EBV were all negative in B, T, and NK cells. In the four non-transplant patients, the median time to EBV reactivation was 35 days (range: 1-328 days) after diagnosis of the primary disease. EBV was detected in one or two subsets of B, T, or NK cells, but not simultaneously in all three subsets. These patients received a combination chemotherapy targeting at the primary disease, with 3 patients achieving EBV negativity, and the median time to be negative was 40 days (range: 13-75 days). CONCLUSION In hematologic malignancy patients after allo-HSCT, EBV reactivation commonly involves B, T, and NK cells, with a significantly higher viral load in B cells compared to T and NK cells. Rituximab is effective for EBV clearance. In non-transplant patients, EBV reactivation is restricted to one or two lymphocyte subsets, and clearance is slower, highlighting the need for prompt anti-tumor therapy.
Humans ; Hematologic Neoplasms/virology* ; Herpesvirus 4, Human/physiology* ; Epstein-Barr Virus Infections ; Hematopoietic Stem Cell Transplantation ; Virus Activation ; Lymphocyte Subsets/virology* ; Flow Cytometry ; Killer Cells, Natural/virology* ; Male ; Female ; B-Lymphocytes/virology* ; Viral Load ; Adult ; T-Lymphocytes/virology* ; Middle Aged

Hepatitis B is a global public health concern. Inducing hepatitis B surface antibody (HBsAb) through vaccination is a crucial preventive strategy. However, individuals show varying immune responses to the hepatitis B vaccine. Based on HBsAb levels, individuals can be categorized as high responders, low responders, or non-responders. T cells and their subsets play critical roles in modulating this response, and the composition of the T cell receptor (TCR) repertoire also influences immune responsiveness. Investigating the characteristics of T cells, their subsets, and TCR repertoires in individuals with differential responses post-vaccination may provide theoretical guidance for optimizing vaccine design and immunization strategies.
Humans ; Hepatitis B Vaccines/immunology* ; Hepatitis B/immunology* ; Vaccination ; Hepatitis B Antibodies/blood* ; T-Lymphocytes/immunology* ; Receptors, Antigen, T-Cell/immunology* ; Hepatitis B Surface Antigens/immunology* ; T-Lymphocyte Subsets/immunology*

OBJECTIVE: To observe the levels of soluble programmed cell death protein 1 (sPD-1) and soluble programmed cell death ligand 1 (sPD-L1) in peripheral blood of lymphoma patients, and reveal their clinical significances. METHODS: The peripheral blood specimens and clinical data of 64 newly diagnosed lymphoma patients and 30 healthy volunteers were collected. The levels of sPD-1 and sPD-L1 were detected by enzyme-linked immunosorbent assay (ELISA), and their correlations with clinical characteristics of the patients including pathological type, stage, lactate dehydrogenase (LDH) level, T cell subsets were analyzed. RESULTS: The levels of both sPD-1 and sPD-L1 in peripheral blood of lymphoma patients were higher than those of normal controls (P <0.05). There were no significant differences in sPD-1 and sPD-L1 levels in peripheral blood between Hodgkin lymphoma and non-Hodgkin lymphoma patients. Different pathological subtypes of lymphoma had different levels of sPD-1. The level of sPD-1 in patients with T-cell lymphoma was higher than that in patients with B-cell lymphoma (P =0.001). The levels of both sPD-1 and sPD-L1 in patients with Ann Arbor stage III and IV were higher than those in patients with stage I and II (P <0.05). The level of sPD-L1 in patients with abnormally increased LDH was higher than that in patients with normal LDH (P =0.001), but there was no significant difference in sPD-1 level. T cell subset analysis showed that the level of sPD-L1 was negatively correlated to CD4⁺ T cell content (r =-0.265). CONCLUSION The levels of sPD-1 and sPD-L1 in peripheral blood of lymphoma patients are related to the pathological type, Ann Arbor stage, LDH content and T cell subsets, and will be potential biomarkers in predicting the prognosis of lymphoma.
Humans ; Clinical Relevance ; Prognosis ; T-Lymphocyte Subsets/metabolism* ; Lymphoma, T-Cell, Peripheral ; Enzyme-Linked Immunosorbent Assay ; B7-H1 Antigen/metabolism*

OBJECTIVE: To investigate the distribution of bone marrow lymphocyte subsets in patients with myelodysplastic syndrome(MDS),the proportion of activated T cells with immunophenotype CD3⁺HLA-DR⁺ in the lymphocytes and its clinical significance, and to understand the effects of different types of MDS, different immunophenotypes, and different expression levels of WT1 on the proportion of lymphocyte subsets and activated T cells. METHODS: The immunophenotypes of 96 MDS patients, the subsets of bone marrow lymphocytes and activated T cells were detected by flow cytometry. The relative expression of WT1 was detected by real-time fluorescent quantitative PCR, and the first induced remission rate (CR1) was calculated, the differences of lymphocyte subsets and activated T cells in MDS patients with different immunophenotype, different WT1 expression, and different course of disease were analyzed. RESULTS: The percentage of CD4⁺T lymphocyte in MDS-EB-2, IPSS high-risk, CD34⁺ cells >10%, and patients with CD34⁺CD7⁺ cell population and WT1 gene overexpression at intial diagnosis decreased significantly (P<0.05), and the percentage of NK cells and activated T cells increased significantly (P<0.05), but there was no significant difference in the ratio of B lymphocytes. Compared with the normal control group, the percentage of NK cells and activated T cells in IPSS-intermediate-2 group was significantly higher(P<0.05), but there was no significant difference in the percentage of CD3⁺T, CD4⁺T lymphocytes. The percentage of CD4⁺T cells in patients with complete remission after the first chemotherapy was significantly higher than in patients with incomplete remission(P<0.05), and the percentage of NK cells and activated T cells was significantly lower than that in patients with incomplete remission (P<0.05). CONCLUSION In MDS patients, the proportion of CD3⁺T and CD4⁺T lymphocytes decreased, and the proportion of activated T cells increased, indicating that the differentiation type of MDS is more primitive and the prognosis is worse.
Humans ; Lymphocyte Subsets ; Myelodysplastic Syndromes/diagnosis* ; Bone Marrow ; B-Lymphocytes ; Killer Cells, Natural ; Flow Cytometry ; T-Lymphocyte Subsets

Objective: T lymphocyte exhaustion is an important component of immune dysfunction. Therefore, exploring peripheral blood-exhausted T lymphocyte features in patients with hepatitis B virus-related acute-on-chronic liver failure may provide potential therapeutic target molecules for ACLF immune dysfunction. Methods: Six cases with HBV-ACLF and three healthy controls were selected for T-cell heterogeneity detection using the single-cell RNA sequencing method. In addition, exhausted T lymphocyte subpopulations were screened to analyze their gene expression features, and their developmental trajectories quasi-timing. An independent sample t-test was used to compare the samples between the two groups. Results: Peripheral blood T lymphocytes in HBV-ACLF patients had different differentiation trajectories with different features distinct into eight subpopulations. Among them, the CD4(+)TIGIT(+) subsets (P = 0.007) and CD8(+)LAG3(+) (P = 0.010) subsets with highly exhausted genes were significantly higher than those in healthy controls. Quasi-time analysis showed that CD4(+)TIGIT(+) and CD8(+)LAG3(+) subsets appeared in the late stage of T lymphocyte differentiation, suggesting the transition of T lymphocyte from naïve-effector-exhausted during ACLF pathogenesis. Conclusion: There is heterogeneity in peripheral blood T lymphocyte differentiation in patients with HBV-ACLF, and the number of exhausted T cells featured by CD4(+)TIGIT(+)T cell and CD8(+)LAG3(+) T cell subsets increases significantly, suggesting that T lymphocyte immune exhaustion is involved in the immune dysfunction of HBV-ACLF, thereby identifying potential effective target molecules for improving ACLF patients' immune function.
Humans ; Hepatitis B virus ; Acute-On-Chronic Liver Failure/pathology* ; Hepatitis B, Chronic ; T-Lymphocyte Subsets/pathology* ; Receptors, Immunologic

To explore the application of IL-6, PCT, T lymphocyte subsets and TIGIT expression on T lymphocytes in the evaluation of Crohn's disease status. Using a cross-sectional study, total of 119 confirmed patients with Crohn's disease who were treated in the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine from June 2020 to December 2022 were selected. The age range was 18-59 years old, and the median age (interquartile range) was 37 (29, 45) years old, including 57 cases in active disease group (30 males, 27 females), 62 cases in disease remission group (33 males, 29 females); 50 healthy control groups (27 males, 23 females), the age range was 19-60 years old, and the median age (interquartile range) was 38 (31, 46) years old. The level of IL-6 was detected by flow fluorescence microsphere method, the concentration of PCT was detected by immunochromatography, and the levels of T lymphocyte subsets and TIGIT were detected by flow cytometry. The differences and correlations between the detection indicators in each group were compared, logistic regression was used to analyze the factors influencing the progression of Crosne's disease and the clinical value of each detection indicator was analyzed by ROC curve. The results showed that there were no statistically significant differences in age and gender among the control group, the remission group, and the active group (H=1.422,χ²=0.020;P=0.491, P=0.990); in the active group, IL-6 was 17.55(9.67, 21.72)pg/ml, PCT was 0.38(0.14, 0.43)ng/ml, CD3⁺CD4⁺ was 35.47%±6.01%, CD3⁺CD8⁺ was 30.50%±5.20%, TIGIT was 25.08%±6.30%; in the remission group, IL-6 was 8.46(5.21, 10.04) pg/ml, PCT was 0.26(0.11, 0.35) ng/ml, CD3⁺CD4⁺ was 37.62%±4.86%, CD3⁺CD8⁺ was 28.30%±5.28%, TIGIT was 34.22%±5.45%; in the control group, IL-6 was 6.13(3.57, 8.12)pg/ml, PCT was 0.17(0.10, 0.21)ng/m, CD3⁺CD4⁺ was 39.74%±3.94%, CD3⁺CD8⁺ was 26.59%±4.50%, and TIGIT was 37.64%±6.22%.There were significant differences in IL-6, PCT, CD3⁺CD4⁺%, CD3⁺CD8⁺%, and TIGIT among the three groups(H=58.688, H=18.003, F=9.600, F=8.124, F=65.059;P<0.001, P<0.001, P<0.001, P<0.001, P<0.001), Among them, IL-6 and TIGIT in the active group were significantly different from those in the remission group (P<0.001, P<0.001), and only TIGIT was significantly different between the remission group and the control group (P=0.007);Spearman correlation analysis showed that the expression of TIGIT on T lymphocytes was negatively correlated with the levels of IL-6; the results of Logistic regression analysis showed that IL-6, PCT and TIGIT were independent factors affecting the progression of Crohn's disease;Comparing the ROC curves of the active group and the remission group, found that TIGIT was significantly different from PCT, CD3⁺CD4⁺, CD3⁺CD8⁺(Z=4.011, Z=4.091, Z=4.157; P<0.001, P<0.001, P<0.001), no statistical difference with IL-6 (Z=1.193, P=0.233). Selected the combined detection of IL-6 and TIGIT with the best AUC area and Youden index, which shows that the clinical value is improved, the AUC area of IL-6+TIGIT was significantly different from that of IL-6 (Z=2.674, P=0.008). In summary, TIGIT of T lymphocytes and IL-6 detection may be valuable in the diagnosis and treatment of Crohn's disease, and the combined detection of TIGIT and IL-6 may be meaningful for evaluating the status of Crohn's disease.
Male ; Female ; Humans ; Adult ; Adolescent ; Young Adult ; Middle Aged ; Interleukin-6 ; Crohn Disease/diagnosis* ; Cross-Sectional Studies ; T-Lymphocyte Subsets ; Receptors, Immunologic

To explore the application of IL-6, PCT, T lymphocyte subsets and TIGIT expression on T lymphocytes in the evaluation of Crohn's disease status. Using a cross-sectional study, total of 119 confirmed patients with Crohn's disease who were treated in the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine from June 2020 to December 2022 were selected. The age range was 18-59 years old, and the median age (interquartile range) was 37 (29, 45) years old, including 57 cases in active disease group (30 males, 27 females), 62 cases in disease remission group (33 males, 29 females); 50 healthy control groups (27 males, 23 females), the age range was 19-60 years old, and the median age (interquartile range) was 38 (31, 46) years old. The level of IL-6 was detected by flow fluorescence microsphere method, the concentration of PCT was detected by immunochromatography, and the levels of T lymphocyte subsets and TIGIT were detected by flow cytometry. The differences and correlations between the detection indicators in each group were compared, logistic regression was used to analyze the factors influencing the progression of Crosne's disease and the clinical value of each detection indicator was analyzed by ROC curve. The results showed that there were no statistically significant differences in age and gender among the control group, the remission group, and the active group (H=1.422,χ²=0.020;P=0.491, P=0.990); in the active group, IL-6 was 17.55(9.67, 21.72)pg/ml, PCT was 0.38(0.14, 0.43)ng/ml, CD3⁺CD4⁺ was 35.47%±6.01%, CD3⁺CD8⁺ was 30.50%±5.20%, TIGIT was 25.08%±6.30%; in the remission group, IL-6 was 8.46(5.21, 10.04) pg/ml, PCT was 0.26(0.11, 0.35) ng/ml, CD3⁺CD4⁺ was 37.62%±4.86%, CD3⁺CD8⁺ was 28.30%±5.28%, TIGIT was 34.22%±5.45%; in the control group, IL-6 was 6.13(3.57, 8.12)pg/ml, PCT was 0.17(0.10, 0.21)ng/m, CD3⁺CD4⁺ was 39.74%±3.94%, CD3⁺CD8⁺ was 26.59%±4.50%, and TIGIT was 37.64%±6.22%.There were significant differences in IL-6, PCT, CD3⁺CD4⁺%, CD3⁺CD8⁺%, and TIGIT among the three groups(H=58.688, H=18.003, F=9.600, F=8.124, F=65.059;P<0.001, P<0.001, P<0.001, P<0.001, P<0.001), Among them, IL-6 and TIGIT in the active group were significantly different from those in the remission group (P<0.001, P<0.001), and only TIGIT was significantly different between the remission group and the control group (P=0.007);Spearman correlation analysis showed that the expression of TIGIT on T lymphocytes was negatively correlated with the levels of IL-6; the results of Logistic regression analysis showed that IL-6, PCT and TIGIT were independent factors affecting the progression of Crohn's disease;Comparing the ROC curves of the active group and the remission group, found that TIGIT was significantly different from PCT, CD3⁺CD4⁺, CD3⁺CD8⁺(Z=4.011, Z=4.091, Z=4.157; P<0.001, P<0.001, P<0.001), no statistical difference with IL-6 (Z=1.193, P=0.233). Selected the combined detection of IL-6 and TIGIT with the best AUC area and Youden index, which shows that the clinical value is improved, the AUC area of IL-6+TIGIT was significantly different from that of IL-6 (Z=2.674, P=0.008). In summary, TIGIT of T lymphocytes and IL-6 detection may be valuable in the diagnosis and treatment of Crohn's disease, and the combined detection of TIGIT and IL-6 may be meaningful for evaluating the status of Crohn's disease.
Male ; Female ; Humans ; Adult ; Adolescent ; Young Adult ; Middle Aged ; Interleukin-6 ; Crohn Disease/diagnosis* ; Cross-Sectional Studies ; T-Lymphocyte Subsets ; Receptors, Immunologic