scholarly journals This Is a Title: Cytarabine Combined with PD-1 Inhibitor in the Treatment of R/R-AML: A Report of 3 Cases and Literature Review

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 26-26
Author(s):  
Yu Wang ◽  
Chuanyan Jiang ◽  
Xi Yang ◽  
Jingying Dai ◽  
Mengying Zou ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Treg Cells ◽  
Hematological Toxicity ◽  
High Dose ◽  
Dynamic Changes ◽  
Cd8 T Lymphocytes ◽  
Tnf Α ◽  
High Dose Cytarabine

Objectives: To explore the efficacy and safety of high-dose cytarabine combined with PD-1 inhibitors and demethylation drugs in relapsed and refractory acute myeloid leukemia (R/R-AML) in Chinaand to investigatethe dynamic changes of Treg cells, CD4+ T cells, CD8+ T cells, TNF-α, INF-γ, and IL-6 in the prognosis of the disease. Methods:A total of three patients with R/R-AML treated in our department were included in the study. None of the three patients had received at least two courses of standard chemotherapy before and did not obtain remission.The cellular immunity and cytokines were evaluated on the 1st, 8th, 15th, and 22nd day of the treatment.In the study,eligible R/ R-AML patients (n=3) were treated with azacytidine 75mg/m2 d1-d7, cytarabine 2g/m2 d1-d5, PD-1 inhibitor 200mg d1、d14.The efficacy were evaluated by CR, PR, ORR, PFS, OS, and ED. The safety were evaluated by hematological and non-hematological toxicity. Results: Among the three patients, one patient achieved CR, and one patient achieved PR. The patient who achieved CR successfully underwent allo-HSCT. One patient did not achieve remission and died of disease progression. Three patients were well tolerated to chemotherapy, and non-hematological toxicity was mainly respiratory tract infection, gastrointestinal reaction, and liver function damage.At present, no immune-related tissue injury was observed. Grade III-IV hematologic toxicity was the major adverse reaction, and the longest duration of agranulocytosis was 22 days.The proportion of Treg cells decreased, and the proportion of CD4+ T cells and CD8+ T lymphocytes increased in 2 patients after treatment. One patient received CR and underwent allo-HSCT. One patient showed an increase in the proportion of Treg cells, but there was no significant dynamic change in CD4+ T lymphocytes and CD8+ T lymphocytes. INF-γ increased in 1 patient. Dynamic changes in IL-10, IL-6, and TNF-α were not observed. Conclusions: PD-1 inhibitor combined with high dose cytarabine based chemotherapy may be a salvage treatment for R/R-AML. The dynamic changes of CD4+ T lymphocyte, CD8+ T lymphocyte, Treg cell, and INF-α may reflect the therapeutic effect in advance. Disclosures No relevant conflicts of interest to declare.

scholarly journals Increase in inflammatory T cell subsets in atrial fibrillation: the missing link underlying inflammation in AF

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I.E Dumitriu ◽  
P Dimou ◽  
S Kaur ◽  
S Dinkla ◽  
J.C Kaski ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Inflammatory Cytokines ◽  
T Lymphocyte ◽  
Treg Cells ◽  
Funding Source ◽  
Functional Assays

Abstract Background The precise role of inflammation in the development and perpetuation of atrial fibrillation (AF) is yet to be fully uncovered. T lymphocytes have pivotal roles in orchestrating inflammation. Specialised subsets of lymphocytes either promote or prevent inflammation. We are investigating a unique subset of lymphocytes, the CD4+CD28null T cells that expand in patients with chronic inflammation. These cells secrete high levels of pro-inflammatory cytokines and have cytolytic function. CD4+CD28null T cells are normally maintained under control by regulatory T cells (Treg), a specialised subset of T lymphocytes with suppressive function that maintain immune homeostasis and prevent pathogenic immune responses. The role of CD4+CD28null and Treg cells has not been investigated in AF. Purpose We hypothesised that in AF the balance between pro-inflammatory and regulatory T lymphocytes is skewed in favour of inflammatory T cells, which may sustain inflammation in AF. Methods Circulating CD4+CD28null T lymphocytes and Tregs were quantified by flow cytometry in paroxysmal and persistent AF patients and healthy controls (n=30). Inflammatory cytokines were quantified in serum and the function of T lymphocyte subsets was investigated using ex vivo functional assays. Results CD4+CD28null T lymphocytes were significantly increased in the circulation of AF patients compared to controls. Of note, a higher proportion of patients with persistent AF showed an increase in inflammatory CD4+CD28null T lymphocytes compared to patients with paroxysmal AF. A marked reduction in Treg cells was present in AF patients compared to controls. Functional assays showed that IL-7 and IL-15 cytokines were responsible for CD4+CD28null T lymphocyte expansion in AF patients. Conclusions We show that patients with AF have marked changes in T lymphocytes subsets: pro-inflammatory CD4+CD28null T cells increase significantly, whilst anti-inflammatory Tregs are significantly reduced. We show for the first time that the cytokines IL-7 and IL-15 are the main drivers of CD4+CD28null T cell expansion in AF patients. These novel findings may reveal novel therapeutic strategies (e.g. cytokine blockade) to re-establish the balance between pro- and anti-inflammatory mechanisms at work in AF to improve patient outcomes. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

scholarly journals Causes of T lymphocyte activation in HIV-infected patients coinfected with hepatitis C virus

2016 ◽  
Vol 88 (11) ◽  
pp. 22-28
Author(s):  
K V Shmagel ◽  
N G Shmagel ◽  
L B Korolevskaya ◽  
E V Saydakova ◽  
V A Chereshnev
Keyword(s):  
T Cells ◽  
Hepatitis C ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
T Lymphocyte ◽  
Cell Activation ◽  
Lymphocyte Activation ◽  
Cd8 T Cell ◽  
Cd8 T Lymphocytes

Aim. To establish the causes of T lymphocyte activation in human immunodeficiency virus (HIV)-infected patients coinfected with hepatitis C (HCV) who are adherent to their antiretroviral therapy regimen and interferon untreated. Subjects and methods. Examinations were made in 62 people who were HIV+HCV-positive (n=21), HIV+HCV-negative (n=21), and noninfected volunteers (n=20). The activation (CD38+HLA-DR+) and proliferation (Ki-67+) of CD4+ and CD8+ T lymphocytes were estimated. The blood concentration of intestinal fatty acid-binding protein (I-FABP) was determined. Results. The proportion of activated cells among the CD4+ T lymphocytes was equal in the HIV+HCV-positive and HIV+HCV-negative groups. But these indicators were statistically significantly higher than those in the controls (HIV- HCV-). CD8+ T cell activation was greater in the HIV/HCV-coinfected patients than that in the other groups and that was higher in the HIV monoinfected than in the noninfected. The blood I-FABP concentrations were elevated in the HIV+HCV-positive and HIV+HCV groups compared with those in the HIV-HCV-negative group, but these did not differ among themselves. In the HIV+HCV-negative patients, CD4+ and CD8+ T cell activation directly and statistically significantly correlated with blood I-FABP levels. In the HIV+HCV-positive group, this correlation remained only for CD4+ T lymphocytes. CD8+ T cell activation in HIV/HCV-coinfected patients was unrelated to I-FABP concentrations. Conclusion. The increased activation of CD4+ and CD8+ T lymphocytes in HIV monoinfection was found to be associated with intestinal epithelial destruction and unrelated to cell division processes. In HIV/HCV coinfection, the activated state of CD4+ T cells is determined by both the level of proliferative processes and impairment of the intestinal barrier and that of CD8+ T cells is only by proliferation.

scholarly journals Dietary strawberries increase the proliferative response of CD3/CD28-activated CD8+ T cells and the production of TNF-α in lipopolysaccharide-stimulated monocytes from obese human subjects

2013 ◽  
Vol 110 (11) ◽  
pp. 2011-2019 ◽  
Author(s):  
Susan J. Zunino ◽  
David H. Storms ◽  
Tammy L. Freytag ◽  
Bruce E. Mackey ◽  
Ling Zhao ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
T Lymphocyte ◽  
Mononuclear Cells ◽  
Global Changes ◽  
Obese People ◽  
Activated T Cells ◽  
Double Blind ◽  
Freeze Dried ◽  
Tnf Α

Obesity increases the risk of developing bacterial and viral infections compared with normal weight. In a 7-week double-blind, randomised, cross-over trial, twenty obese volunteers (BMI between 30 and 40 kg/m2) were fed freeze-dried strawberry powder or strawberry-flavoured placebo preparations to determine the effects of dietary strawberries on immune function. Blood was collected at six time points during the study and peripheral blood mononuclear cells (PBMC) were isolated at each time point and activated with CD3 plus CD28 antibodies (T-lymphocyte activation) or lipopolysaccharide (LPS, monocyte activation). Interferon-γ, TNF-α, IL-4 and IL-10 were measured in supernatants from the activated T cells. Supernatants from the activated monocytes were analysed for the production of TNF-α, IL-1β, IL-6 and IL-8. PBMC were pre-stained with PKH (Paul Karl Horan) dye and activated with CD3 plus CD28 antibodies to determine the proliferative responses of CD4+ and CD8+ T-lymphocytes by flow cytometry. To detect global changes in gene expression, microarray analysis was performed on LPS- and vehicle-treated PBMC from two subjects before and after the strawberry intervention. No difference was observed for the production of T-cell cytokines between the intervention groups. The production of TNF-α was increased in the supernatants from LPS-activated PBMC in the group consuming strawberries compared with the placebo. A modest increase in the proliferation of the CD8+ T-lymphocyte population was observed at 24 h post-activation. These data suggest that dietary strawberries may increase the immunological response of T-lymphocytes and monocytes in obese people who are at greater risk for developing infections.

scholarly journals Clinical Outcome Prediction in COVID-19 Patients by Lymphocyte Subsets Analysis and Monocytes’ iTNF-α Expression

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 735
Author(s):  
Gabriele Madonna ◽  
Silvia Sale ◽  
Mariaelena Capone ◽  
Chiara De Falco ◽  
Valentina Santocchio ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
T Lymphocyte ◽  
Inflammatory Cells ◽  
Retrospective Assessment ◽  
Cd8 T Lymphocytes ◽  
Cd8 T Lymphocyte ◽  
Tnf Α ◽  
Cellular Mediators ◽  
Novel Coronavirus

In December 2019, a novel coronavirus, “SARS-CoV-2”, was recognized as the cause of coronavirus disease 2019 (COVID-19). Several studies have explored the changes and the role of inflammatory cells and cytokines in the immunopathogenesis of the disease, but until today, the results have been controversial. Based on these premises, we conducted a retrospective assessment of monocyte intracellular TNF-α expression (iTNF-α) and on the frequencies of lymphocyte sub-populations in twenty-five patients with moderate/severe COVID-19. We found lymphopenia in all COVID-19 infected subjects compared to healthy subjects. On initial observation, in patients with favorable outcomes, we detected a high absolute eosinophil count and a high CD4+/CD8+ T lymphocytes ratio, while in the Exitus Group, we observed high neutrophil and CD8+ T lymphocyte counts. During infection, in patients with favorable outcomes, we observed a rise in the lymphocyte count, in the monocyte and in Treg lymphocyte counts, and in the CD4+ and in CD8+ T lymphocytes count but a reduction in the CD4+/CD8+ T lymphocyte ratio. Instead, in the Exitus Group, we observed a reduction in the Treg lymphocyte counts and a decrease in iTNF-α expression. Our preliminary findings point to a modulation of the different cellular mediators of the immune system, which probably play a key role in the outcomes of COVID-19.

scholarly journals Flow cytometric analysis of T lymphocytes and cytokines in aqueous humor of patients with varicella zoster virus-mediated acute retinal necrosis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hao Kang ◽  
Yunbo Wei ◽  
Ming Liu ◽  
Di Yu ◽  
Yong Tao
Keyword(s):  
T Lymphocytes ◽  
Varicella Zoster Virus ◽  
Aqueous Humor ◽  
T Lymphocyte ◽  
Lymphocyte Subsets ◽  
Flow Cytometric Analysis ◽  
T Lymphocyte Subsets ◽  
Varicella Zoster ◽  
Flow Cytometric ◽  
Cd8 T Lymphocytes

Abstract Background The purpose of this study is to investigate the aqueous humor (AH) T lymphocyte subsets and cytokines of acute retinal necrosis (ARN) to elucidate the immunologic inflammatory features of this disorder. Methods Three patients with ARN infected with varicella zoster virus (VZV) who underwent multiple intravitreal injections of ganciclovir were enrolled in this study. The control group consisted of four non-infectious patients with acute anterior uveitis (AAU). Flow cytometric analysis was performed on the lymphocyte subsets from the AH and peripheral blood (PB) samples during the active phase of intraocular inflammation. Five inflammatory cytokines were measured in each AH sample and various clinical characteristics were also assessed. Results VZV deoxyribonucleic acid (DNA) was detected by real-time polymerase chain reaction (PCR) in AH from all the ARN patients, who showed higher CD8+ T lymphocytes population in AH than the AAU patients (p = 0.006). CD4/CD8 ratios of T lymphocytes and the percentage of CD8 + CD25+ T lymphocytes in AH were significantly lower in ARN than in AAU (p = 0.006; p = 0.012). In the ARN patients, the percentages of CD4+ and CD8+ T lymphocytes in AH were higher than those found in PB. The percentage of CD4 + CD25+ T lymphocytes in AH was significantly higher than the proportion in PB in the AAU patients (p = 0.001). Immunoregulatory cytokine Interleukin-10 in AH was significantly elevated in the ARN patients in comparison with the case of the AAU patients (p = 0.036). In ARN, the copy number of VZV DNA in AH positively correlated with the percentage of CD8+ T lymphocytes in AH and negatively correlated with the CD4/CD8 ratio in AH during the course of disease treatment (p = 0.009, r = 0.92; p = 0.039, r = − 0.834). Conclusion The ARN patients caused by VZV had different intraocular T lymphocyte subsets and cytokines profile than those of the non-infectious patients. High percentages of CD8+ T lymphocytes and low CD4/CD8 T cell ratios may be a potential biomarker for diagnosis of viral-infectious uveitis. T lymphocytes examination at the inflammatory sites has the potential to become a useful research tool for differentiating viral and non-viral uveitis.

scholarly journals Lipocortin 1 binding sites on human T-cells: The population of cells with the binding sites is larger in CD8 T-lymphocytes than in CD4 T-lymphocytes

IUBMB Life ◽  
1996 ◽  
Vol 40 (6) ◽  
pp. 1167-1173
Author(s):  
Ha Won Kim ◽  
Euna Choi ◽  
Bin Yoo ◽  
Jung Ryul Choi ◽  
Young Min Park ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Binding Sites ◽  
Cd8 T Lymphocytes ◽  
Human T Cells

scholarly journals Increased Frequency of Regulatory T Cells and T Lymphocyte Activation in Persons with Previously Treated Extrapulmonary Tuberculosis

2011 ◽  
Vol 19 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Alexandre S. de Almeida ◽  
Christina T. Fiske ◽  
Timothy R. Sterling ◽  
Spyros A. Kalams
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Pulmonary Tuberculosis ◽  
Treg Cell ◽  
T Lymphocyte ◽  
Extrapulmonary Tuberculosis ◽  
Lymphocyte Activation ◽  
Content Type ◽  
T Lymphocyte Activation ◽  
Previously Treated

ABSTRACTExtrapulmonary tuberculosis may be due to underlying immune compromise. Immunosuppressive regulatory T cells (Treg cells), and CD4+T lymphocytes in general, are important in the host immune response toMycobacterium tuberculosis. We evaluated T lymphocytes from patients after recovery from extrapulmonary tuberculosis, which may reflect conditions beforeM. tuberculosisinfection. A case-control study was conducted among HIV-uninfected adults with previously treated extrapulmonary tuberculosis and 3 sets of controls: (i) subjects with previously treated pulmonary tuberculosis, (ii) close tuberculosis contacts withM. tuberculosisinfection, and (iii) close tuberculosis contacts with no infection. Monocyte-depleted peripheral blood mononuclear cells (PBMC-M) were stained for CD4+CD25hiCD127lowFoxP3+cell (Treg cell) and T lymphocyte activation. Both characteristics were compared as continuous variables between groups with the Kruskal-Wallis test. There were 7 extrapulmonary tuberculosis cases, 18 pulmonary tuberculosis controls, 17 controls withM. tuberculosisinfection, and 18 controls withoutM. tuberculosisinfection. The median Treg cell proportion was highest among persons with previous extrapulmonary tuberculosis (1.23%) compared to subjects with pulmonary tuberculosis (0.56%), latentM. tuberculosisinfection (0.14%), or noM. tuberculosisinfection (0.20%) (P= 0.001). The median proportion of CD4+T lymphocytes that expressed the activation markers HLA-DR and CD38 was highest for CD4+T lymphocytes from persons with previous extrapulmonary tuberculosis (0.79%) compared to subjects with pulmonary tuberculosis (0.44%), latentM. tuberculosisinfection (0.14%), or noM. tuberculosisinfection (0.32%) (P= 0.005). Compared with controls, persons with previously treated extrapulmonary tuberculosis had the highest Treg cell frequency, but also the highest levels of CD4+T lymphocyte activation. Immune dysregulation may be a feature of individuals at risk for extrapulmonary tuberculosis.

IMMU-49. DYNAMIC CHANGES AND PROGNOSTIC VALUE OF PERIPHERAL BLOOD LYMPHOCYTE SUBSETS IN INTRACRANIAL GERM CELL TUMORS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi103-vi104
Author(s):  
Hairong Wang ◽  
Cheng-Cheng Guo ◽  
Hongyu Chen ◽  
Yang Qun-ying ◽  
Zhong-ping Chen
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Germ Cell ◽  
Peripheral Blood ◽  
B Lymphocyte ◽  
Germ Cell Tumors ◽  
T Helper ◽  
Tumor Treatment ◽  
Dynamic Changes ◽  
Intracranial Germ Cell Tumors

Abstract OBJECTIVE This study was designed to retrospectively analyze the dynamic changes of peripheral blood lymphocyte subsets and prognosis among patients with intracranial germ cell tumors. METHODS A total of 150 intracranial germ cell tumors patients diagnosed between June 2011 till November 2019 were retrospectively investigated. Peripheral blood total T lymphocytes (CD3+) percentage, T helper/inducible lymphocytes(CD3+CD4+)percentage, T inhibitory/toxic lymphocytes (CD3+CD8+) percentage, B lymphocyte (CD19+) percentage, NK lymphocyte (CD3/CD16+CD56+) percentage, regulatory T cells (CD4+CD25+,CD8+CD25+), and T helper/toxic lymphocyte ratio (CD4+/CD8+ ratio) were quantified by flow cytometry analysis. Clinical information was extracted from the database in Sun Yat-sen University Cancer Center and survival data was confirmed through outpatient visits and telephone follow-up. RESULTS T lymphocytes population was increased after anti-tumor treatment, with significant difference of total T lymphocytes (CD3+), inhibitory/toxic T cells (CD3+CD8+) and regulatory T cells (CD4+CD25+ and CD8+CD25+), (p=0.008, p=0.000, p=0.008 and p=0.001 respectively), while B lymphocytes(CD19+) decreased after chemotherapy(p=0.003). The dynamic levels of T lymphocyte and B lymphocyte subpopulation after chemotherapy did not present significant differences between gender, age, and locations of tumors (p >0.05), except CD4+CD25+ T cells in younger children (age< 16 years older) increased significantly than the elder (age >16), p=0.04. Patients with increased CD19+ B cells presented significant suboptimal outcomes compared with the no increased (p=0.024). Similarly, increased CD3+ T cells, CD3+CD8+ T cells, CD4+CD25+ T cells reduced the risk of death (p=0.006, p=0.019, p=0.042 respectively). Multivariate Cox Regression analysis showed: increased CD19+ B cells, p=0.04, HR=1.688, 95%CI=1.025-2.779. CONCLUSION After anti-tumor treatment, cell-mediated immunity activated, enhanced, and dominated in anti-tumor response. An increased level of CD19+ subsets was an independent predictor for inferior overall survival. Systemic circulating T cells immunity played an important role and mediating antitumor responses may pave the road for new immunity strategies.

Abstract 14723: Autoreactive T Lymphocytes Activate Cardiac Endothelium Independently of Tnf-α and Cause Endothelial Dysfunction Through Exosomes in Experimental Autoimmune Myocarditis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Filip Rolski ◽  
Marcin Czepiel ◽  
Kazimierz Weglarczyk ◽  
Maciej Siedlar ◽  
Gabriela Kania ◽  
...  
Keyword(s):  
T Cells ◽  
Endothelial Dysfunction ◽  
T Lymphocytes ◽  
Conditioned Medium ◽  
Autoimmune Myocarditis ◽  
Autoreactive T Cells ◽  
Tnf Α ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune ◽  
Stimulation Of

Background: Inflammatory heart diseases represent an important clinical problem, nonetheless data regarding activation of cardiac microvascular endothelial cells (MVECs) are limited. Aim: To examine influence of TNF-α and exosomes produced by heart-reactive CD4+ T lymphocytes on activation of cardiac MVECs. Methods: Experimental autoimmune myocarditis (EAM) was induced in wild-type (WT) and TNF-α-deficient (TNF-KO) mice. CD4+ T lymphocytes were isolated from EAM mice at day 21 and activated in vitro to produce conditioned medium and exosomes. Activation of MVECs was assessed by specific assays and leukocyte-to-endothelial adhesion was analysed under shear flow condition using the BioFlux microfluidic system. Results: TNF-KO mice showed lower prevalence of myocarditis when compared to WT mice (50% vs. 90%). Stimulation of MVECs with secretome of antigen-activated autoreactive T cells resulted in upregulation of adhesion molecules (ICAM-1, VCAM-1 and P-selectin), increased ROS and decreased NO production. Addition of anti-TNF-α neutralizing antibodies effectively blocked adhesion of leukocytes to MVECs activated with the conditioned medium. Endothelial activation and dysfunction induced by the conditioned medium were independent of TNF-α produced by T cells. Stimulation of MVECs with T cell-derived exosomes increased ROS and decreased levels of NO and eNOS activation, but exosomes neither increased expression of adhesion molecules in MVECs nor induced their ability to bind leukocytes. Conclusions: TNF-α promotes MVEC activation and EAM development. In this model, autoreactive T cells activate MVECs, and TNF-a produced by MVECs rather than T cells is essential in this process. On the other hand, endothelial dysfunction caused by T cells seems to be mediated mainly by exosomes.

scholarly journals Circulating CD8 T Lymphocytes in Human Immunodeficiency Virus-Infected Individuals Have Impaired Function and Downmodulate CD3ζ, the Signaling Chain of the T-Cell Receptor Complex

Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 585-594 ◽  
Author(s):  
Linda A. Trimble ◽  
Judy Lieberman
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Receptor Complex ◽  
Cd8 T Lymphocytes ◽  
Immunodeficiency Virus ◽  
Specific Cytotoxicity

Although human immunodeficiency virus (HIV)-infected subjects without acquired immunodeficiency syndrome have a high frequency of HIV-specific CD8 T lymphocytes, freshly isolated lymphocytes frequently lack detectable HIV-specific cytotoxicity. However, this effector function becomes readily apparent after overnight culture. To investigate reasons for T-cell dysfunction, we analyzed T-cell expression of the cytolytic protease granzyme A and of CD3ζ, the signaling component of the T-cell receptor complex. An increased proportion of CD4 and CD8 T cells from HIV-infected donors contain granzyme A, consistent with the known increased frequency of activated T cells. In 28 HIV-infected donors with mild to advanced immunodeficiency, a substantial fraction of circulating T cells downmodulated CD3ζ (fraction of T cells expressing CD3ζ, 0.74 ± 0.16 v 1.01 ± 0.07 in healthy donors; P < .0000005). CD3ζ expression is downregulated more severely in CD8 than CD4 T cells, decreases early in infection, and correlates with declining CD4 counts and disease stage. CD3ζ expression increases over 6 to 16 hours of culture in an interleukin-2–dependent manner, coincident with restoration of viral-specific cytotoxicity. Impaired T-cell receptor signaling may help explain why HIV-specific cytotoxic T lymphocytes fail to control HIV replication.

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