HCV coinfection does not alter the frequency of regulatory T cells or CD8+ T cell immune activation in chronically infected HIV+ Chinese subjects

Regulatory T cell (Treg) is a subset of CD4(+) T cells that play a critical role in regulating the immune responses. Human immunodeficiency virus (HIV) infection is associated with T cell abnormalities and alters effector T cell function. There are a large number of patients coinfected with HIV and hepatitis C virus (HCV). Here, we evaluated the proportion of CD4(+) Treg cells expressing CD25 and FOXP3, and the status of immune activation of CD8(+) T cells in 60 Chinese patients chronically infected with HIV and/or HCV. Furthermore, we investigated the influence of highly active antiretroviral therapy (HAART) on the level of Treg cells and immune activated CD8(+) T cells. We observed that the Treg level was upregulated in HIV infection and HCV infection could not enhance this kind of upregulation significantly. The level of Treg cells was negatively correlated with CD4(+) T cell counts and positively correlated with HIV viral loads. We observed considerably elevated CD38 and HLA-DR expression in CD8(+) T cells in HIV-infected subjects but not in HCV-infected patients in comparison to that in healthy controls. There is no significant difference concerning the proportion of CD8(+) T cells expressing CD38 or HLA-DR between HIV-1-monoinfected and HIV/HCV-coinfected patients. After 12-week HAART, the proportion of Treg cells dropped, but still more than the level in healthy controls. HAART could reverse the abnormal immune activation of CD8(+) T cells. The decrease of Tregs did not alter the downregulation of HIV-1-specific CTL responses in these HIV-infected patients after HAART therapy. The level of HIV virus might be the key point for the decline of CTL responses.     

Short-cycle structured intermittent treatment of chronic HIV infection with highly active antiretroviral therapy: Effects on virologic, immunologic, and toxicity parameters

Although continuous highly active antiretroviral therapy (HAART) is effective for many HIV-infected patients, it can be toxic and prohibitive in cost. By decreasing the total amount of time patients receive medications, intermittent HAART could reduce toxicity and cost. Therefore, we initiated a pilot study in which 10 HIV-infected individuals receiving effective therapy that resulted in levels of HIV RNA <50 copies per ml of plasma and CD4(+) T cell counts >300 cells per mm(3) of whole blood received repeated cycles of 7 days on HAART followed by 7 days off of HAART. Patients maintained suppression of plasma viremia for 32-68 weeks. There was no significant increase in HIV proviral DNA or replication-competent HIV in peripheral CD4(+) T cells or HIV RNA in peripheral blood or lymph node mononuclear cells. There was no significant change in CD4(+) T cell counts, no significant increase in CD4(+) or CD8(+) T cells expressing activation markers or producing IFN-gamma in response to HIV, no increase in CD4(+) T cell proliferation to p24 antigen, and no evidence for the development of resistance to HAART medications. There was a significant decrease in serum cholesterol and triglyceride levels. Thus, in this proof-of-concept study, short-cycle intermittent HAART maintained suppression of plasma viremia as well as HIV replication in reservoir sites while preserving CD4(+) T cell counts. In addition, there was a decrease in serum cholesterol and triglyceride levels. Intermittent therapy may be an important strategy to reduce cost and toxicity for HIV-infected individuals.     

Gammadelta T cell activation by chronic HIV infection may contribute to intrahepatic vdelta1 compartmentalization and hepatitis C virus disease progression independent of highly active antiretroviral therapy

HIV and hepatis C virus (HCV) coinfection is frequently associated with rapid progression of HCV-related disease, resulting in a higher risk of cirrhosis. Data suggest that natural T cells expressing the Vdelta1 T cell receptor rearrangement are recruited in the liver of chronically HCV-infected patients and are increased in the peripheral blood of HIV-infected persons. We studied gammadelta T cell distribution in the peripheral blood and liver of HCV-infected and HIV/HCV-coinfected patients in the presence and absence of antiretroviral therapy. We observed that Vdelta1+ T cells releasing helper T cell type 1 cytokines are compartmentalized not only in the liver of HCV+ patients, but also of HIV/HCV-coinfected persons. HIV/HCV patients showed an increased frequency of both peripheral and intrahepatic Vdelta1 natural T lymphocytes, resulting in a higher degree of hepatic inflammation when compared with patients with other liver diseases. Finally, highly active antiretroviral therapy (HAART) was unable to restore Vdelta1T cell circulation to normal levels in chronically HIV-infected persons. We conclude that gammadelta T lymphocytes released from tissue to the bloodstream circulation under the influence of chronic HIV infection may contribute to intrahepatic Vdelta1 compartmentalization and progression of liver disease, independently of HAART.     

Endogenous IL-7 is associated with increased thymic volume in adult HIV-infected patients under highly active antiretroviral therapy

OBJECTIVE: Immune reconstitution after highly active antiretroviral therapy (HAART) in HIV-infected patients has led to an increase in the number of new CD4 T lymphocytes. Neolymphopoiesis in the thymus has been proposed as a mechanism in T-cell regeneration. Nevertheless, factors involved in the regeneration of T cells by thymic-dependent pathways in HIV-infected patients under HAART are still unknown and might be of relevance in HIV infection. The aim of this work was to study the role of IL-7 in the thymic rebound of HIV-infected adults under HAART. DESIGN: To study the association between IL-7 and thymic function-related markers, these variables were measured in 49 antiretroviral-naive HIV-infected patients at baseline and at weeks 12, 24, 36 and 48 of treatment. METHODS: Thymic function-related markers: thymic volume, naive phenotype, and T-cell receptor excision circles (TREC) bearing-cells, were evaluated by computed tomography, flow cytometry, and quantitative polymerase chain reaction, respectively. IL-7 levels were evaluated using a high sensitivity colorimetric enzyme-linked immunosorbent assay. RESULTS: At baseline, we found an inverse correlation between IL-7 levels and thymic function-associated parameters: thymic volume, naive T cells and TREC-bearing cells. After 48 weeks of therapy increased levels of thymic function-related markers along with a significant decrease in IL-7 levels were found. IL-7 levels at baseline were the only independently associated variable with respect to changes in thymic volume at weeks 12, 24 and 48 of follow-up. CONCLUSION: These data suggest that IL-7 plays an important role in thymic rebound in adult HIV-infected patients under HAART.     

Additive effects of IL-2 and protein kinase A type I antagonist on function of T cells from HIV-infected patients on HAART

OBJECTIVE: To explore the basis for a possible immunomodulatory combination therapy with IL-2 and agents inhibiting protein kinase A (PKA) type I. DESIGN: Highly active antiretroviral therapy (HAART) has dramatically improved HIV therapy, but fails to eradicate the virus, and the persistence of HIV-associated immunodeficiency demonstrates the need for additional immunomodulating therapies. We have previously shown that hyperactivation of PKA type I inhibits the function of HIV-infected patient T cells. The separate and combined effect of a PKA type I-selective antagonist (Rp-8-Br-cAMPS) and Interleukin (IL)-2 on the function of T cells from HIV-infected patients on HAART was examined. METHODS: The effect of Rp-8-Br-cAMPS on anti-CD3 stimulated proliferation and IL-2 production and the combined effect with exogenous IL-2 was studied in vitro with cells from 13 HIV-infected patients on HAART and six uninfected controls. RESULTS: The PKA type I-selective antagonist improved cell proliferation (median 1.5-fold, maximal 2.8-fold) and IL-2 production (median 1.5-fold, maximal 2.4-fold) in T cells from HIV-infected patients on HAART, but not in controls. The addition of IL-2 enhanced proliferation of T cells from HIV-infected patients (approximately 1.9-fold) and that of controls (approximately 1.4-fold), but IL-2 had no effect at the concentrations produced by treatment with PKA type I antagonist. However, the combined effect of IL-2 and PKA type I antagonist was additive and resulted in a further increase in T-cell proliferation (median 2.5-fold, maximal 5.8-fold), reaching levels comparable with those of uninfected controls in most of the patients. CONCLUSION: Our findings suggest a basis for a novel strategy in treatment of HIV infection by combining IL-2 therapy and treatment modalities counteracting PKA type I activity with HAART.     

Human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy maintain activated CD8+ T cell subsets as a strong adaptive immune response to cytomegalovirus.

CD8(+) T lymphocyte function specific for human cytomegalovirus (CMV) was evaluated in 14 patients infected with human immunodeficiency virus (HIV) receiving highly active antiretroviral therapy (HAART) and 26 CMV-seropositive donors without HIV infection. Fifty-seven percent of the HIV-infected group had CMV-specific cytolytic activity in freshly isolated peripheral blood mononuclear cells (PBMC) against targets expressing CMV pp65. Both interferon (IFN)-gamma secretion by CD8(+) T cells and the frequency of human leukocyte antigen (HLA)-tetramer-positive T cells in HLA-A*0201-positive HIV-infected subjects correlated with CMV-specific cytolysis. In contrast, PBMC from healthy CMV-seropositive donors did not have either measurable CMV-specific cytolysis or secretion of IFN-gamma without in vitro stimulation. The T helper response to CMV antigens was vigorous in healthy CMV-seropositive donors but low in the cohort of HIV-infected patients. Potent CD8(+) cytotoxic T lymphocyte responses to CMV in HIV-infected patients receiving HAART is the converse of what is found in healthy CMV-seropositive subjects and may be the predominant adaptive immune response against CMV in HIV-infected patients.     

Assessment of the Factors Involving in the Development of Hypothyroidism in HIV-infected Patients: A Case-Control Study

Abstract Objectives: Increased prevalence of thyroid dysfunction has been reported in HIV-infected patients, and recent studies have shown hypothyroidism as the most common thyroid function abnormality in this population, especially after treatment with antiretroviral drugs (HAART). The aim of this study is to assess risk factors of hypothyroidism in HIVinfected patients in Iran. Design: This case-control study was conducted among 15 hypothyroid (cases) and 70 euthyroid (control group) HIV-infected outpatients. Serum Free T4, Free T3, and TSH levels were measured, and data on age, sex, body mass index, opium addiction or injection of illicit drugs, duration of HIV infection and HAART, disease stage, CD4-cell count, opportunistic infection (OI) or malignancy, HCV co-infection, and drug use were collected. Results: We found no association between hypothyroidism in HIV-infected patients and any parameters measured, and P value was not significant for receipt of HAART (0.141), CD4-cell count (0.094), duration of HIV infection (0.474), duration of HAART (0.418), HCV co-infection (0.146), OI (0.566), or receipt of rifampin (0.816). Conclusion: In this study, age, sex, HAART, mean CD4- cell count, duration of HIV infection, HCV co-infection, and OI were not significant risk factors of hypothyroidism in HIV-infected patients. The occurrence of hypothyroidism may be related to other factors or HIV infection itself. Therefore, hypothyroidism should be considered in all HIV-infected patients.     

Abnormal presence of semimature dendritic cells that induce regulatory T cells in HIV-infected subjects

Dendritic cells (DCs), because they orchestrate the immune response to microbes, represent an ideal target for pathogens attempting to evade the immune system. We hypothesized that interactions between human immunodeficiency virus (HIV) and DCs lead to the development of a semimature state, in which DCs migrate to lymph nodes but induce tolerance in T cells, rather than immunity. We found that lymph nodes from untreated HIV-infected subjects contained an abundance of semimature DCs, the disappearance of which correlated with the initiation of highly active antiretroviral therapy (HAART). Such lymph nodes also contained an abundance of T cells that had a regulatory phenotype and that persisted after HAART. Lymph node DCs from untreated HIV-infected subjects cultured with normal allogeneic T cells induced these T cells to adopt the phenotype of regulatory T cells, an ability that was lost after HAART. We conclude that HIV infection correlates with the presence of semimature DCs that stimulate T cell tolerance rather than immunity. These regulatory T cells may contribute to the lack of effective HIV immune responses.     

Recovery of replication-competent virus from CD4 T cell reservoirs and change in coreceptor use in human immunodeficiency virus type 1-infected children responding to highly active antiretroviral therapy

Highly active antiretroviral therapy (HAART) suppresses plasma viremia in most patients with human immunodeficiency virus (HIV) infection. Prospective study of HIV-infected children (n=27) shows that, in 8 of 12 who responded to HAART (>/=0.5 log reduction in plasma HIV RNA), HAART restricted the number of coreceptors used by the predominant HIV isolate (mean number of coreceptors used at baseline was 4, vs. 1 coreceptor used at 6 months after treatment). This decrease was most striking in 6 of 8 children whose HIV coreceptor tropism changed from X4-tropic at baseline to R5-tropic. In 6 of 10 children tested, with plasma HIV RNA levels of <50 copies/mL, R5-tropic virus was isolated from CD4 T cell reservoirs. All the responding children had a significant increase in naive CD4 T cells (P<.05). These results show that persistent HIV T cell reservoirs are present in children and that HAART may influence the number and type of coreceptors used by the predominant virus isolate.     

Effect of HAART on salivary composition and oxidative profile in HIV-infected patients

Although it has been widely suggested that oxidative stress contributes to the pathogenesis of HIV infection, salivary composition and its oxidative related aspects have never been studied in HIV patients, both HAART-treated and untreated. Human saliva and serum were collected and analyzed for various biochemical, redox related and immunological parameters from 43 consenting HIV-infected patients (20 untreated and 23 treated with HAART) and 20 healthy controls, age and gender matched. Saliva composition of HIV infected patients was completely altered but returned to normal following HAART. HIV patients had significantly-increased levels of oxidative stress damaging markers, compared to healthy controls. Carbonyl levels increased by 110% (p=0.005), and superoxide dismutase enzyme (SOD) and antioxidant capacity (ImAnOx) levels by 45% and 16% (0.035) respectively, but returned to normal levels in treated patients (p=0.005, p=0.03 and 0.02 respectively). Also, the significantly-altered salivary composition (pH and lactate dehydrogenase (LDH) enzyme) and concentration (calcium (Ca), magnesium (Mg), albumin, salivary total protein, secretory IgA) of HIV-infected patients reverted to normal following HAART treatment. Salivary analysis may be used for assessing patient status: treated vs untreated, based on the increase or decrease in the concentration of a given salivary parameter in the HIV-untreated group vs controls, and a return to normal following the HAART treatment. Salivary collection is simple, non-invasive and not associated with risk of infection spread. Antioxidants in HIV patients may be recommended, as well as local oral means aimed at resuming salivary functions compromised in HIV patients.     

Down-regulation of interleukin-7 receptor (CD127) in HIV infection is associated with T cell activation and is a main factor influencing restoration of CD4(+) cells after antiretroviral therapy

BACKGROUND: Factors influencing the depletion of CD4(+) cells and the restoration of CD4(+) cells after antiretroviral therapy are not completely understood. Recently, attention has been paid to interleukin (IL)-7 and its receptor (CD127). We analyzed the influence of T cell activation and of suppression of viremia with antiretroviral therapy on this system, as well as its role in CD4(+) cell restoration after long-term antiretroviral therapy. METHODS: IL-7 levels and CD127 expression on several subsets of CD4(+) and CD8(+) T lymphocytes and the activation status (CD38) of these cells were examined at baseline and during 24 months of complete viral suppression under highly active antiretroviral therapy (HAART). RESULTS: A total of 42 individuals with human immunodeficiency virus (HIV) infection and 10 age-matched, uninfected control subjects were examined. Before HAART, IL-7 levels were increased and CD127 expression was decreased. Down-regulation of CD127 was mainly associated with T cell activation and reverted only partially after suppression of detectable plasma HIV RNA with HAART. In a multivariate analysis, CD127 expression on CD8(+) T cells was the main determinant of the extent of CD4(+) cell gains after successful HAART. CONCLUSIONS: The IL-7-CD127 system is impaired in HIV-infected patients. CD127 down-regulation is associated with T cell activation and with CD4(+) cell restoration after HAART.     

Long-term kinetics of T cell production in HIV-infected subjects treated with highly active antiretroviral therapy

The long-term kinetics of T cell production following highly active antiretroviral therapy (HAART) were investigated in blood and lymph node in a group of HIV-infected subjects at early stage of established infection and prospectively studied for 72 wk. Before HAART, CD4 and CD8 T cell turnover was increased. However, the total number of proliferating CD4(+) T lymphocytes, i.e., CD4(+)Ki67(+) T lymphocytes, was not significantly different in HIV-infected (n = 73) and HIV-negative (n = 15) subjects, whereas proliferating CD8(+)Ki67(+) T lymphocytes were significantly higher in HIV-infected subjects. After HAART, the total body number of proliferating CD4(+)Ki67(+) T lymphocytes increased over time and was associated with an increase of both naive and memory CD4(+) T cells. The maximal increase (2-fold) was observed at week 36, whereas at week 72 the number of proliferating CD4(+) T cells dropped to baseline levels, i.e., before HAART. The kinetics of the fraction of proliferating CD4 and CD8 T cells were significantly correlated with the changes in the total body number of these T cell subsets. These results demonstrate a direct relationship between ex vivo measures of T cell production and quantitative changes in total body T lymphocyte populations. This study provides advances in the delineation of the kinetics of T cell production in HIV infection in the presence and/or in the absence of HAART.     

Escape of monocyte-derived dendritic cells of HIV-1 infected individuals from natural killer cell-mediated lysis

OBJECTIVE: To verify whether the in vitro sensitivity of immature dendritic cells (iDC) to lysis by autologous natural killer (NK) cells from HIV-infected individuals might be correlated with HIV disease progression. DESIGN: Both dendritic cells (DC) and interlekin (IL)-2 activated NK cells were obtained from 13 HIV-infected individuals early after seroconversion and not receiving highly active antiretroviral therapy (HAART) and from 14 individuals with chronic HIV infection under HAART. The rate of NK cell-mediated killing of autologous iDC was correlated with classical parameters of HIV evolution. METHODS: Peripheral blood monocytes obtained from the Ficoll-derived leukocyte fraction after adherence to plastic were stimulated with granulocyte-macrophage colony stimulating factor plus IL-4 to induce their differentiation into iDC to be used as target cells in a standard 4-h cytotoxicity assay. A fraction of autologous leukocytes was stimulated with IL-2 to induce activation of NK cells to be used as effector cells. RESULTS: During early HIV infection the extent of ex vivo lysis of monocyte-derived DC by activated autologous NK cells was inversely and directly correlated with the levels of viraemia and with the percentage of circulating CD4 T cells, respectively. In contrast, the capacity of NK cells to kill iDC was lost independently of the levels of plasma viraemia or the concurrence of HAART in chronically infected individuals. Addition of exogenous HIV Tat during the cytotoxicity assay inhibited NK cell-mediated lysis of DC. CONCLUSIONS: NK cell-mediated immune surveillance against infected DC may be effective only during early HIV infection and may not be restored by HAART.     

Cytokine networks are pre-activated in T cells from HIV-infected patients on HAART and are under the control of cAMP

OBJECTIVE: Cytokines seem to play a critical role in HIV infection. The cAMP/protein kinase A (PKA) type I pathway is shown to be hyper-activated and contributes to T-cell immune dysfunction in HIV infection. Here, we analysed firstly the levels of cytokine gene expression in unstimulated CD3+T cells from HIV-infected patients on HAART, and secondly the regulation of cytokine and cytokine-related genes by cAMP agonist and antagonist in anti-CD3 activated T cells in order to understand their effects on cytokine networks. METHODS: Cytokine Macro Array and real-time RT-PCR techniques were used to study cytokine gene expression in T cells of HIV-positive patients. RESULTS: Of the cytokine-related genes analysed 45% were expressed at twofold or higher levels in unstimulated T cells from HIV-infected patients as compared with healthy controls, and one-third of these genes were hypo-responsive upon activation as compared with controls. Furthermore, cAMP modulated levels of expression of a number of cytokine-related genes differently in patient and control T cells. CXCR4, CCR5 and amphiregulin were up-regulated by cAMP agonist, whereas other cytokine-related genes including macrophage inflammatory protein 1 beta, tumour necrosis factor-alpha and lymphotoxin-beta were markedly down-regulated by cAMP agonist in T cells from both HIV-infected patients and controls. Moreover, members of the chemokine/chemokine receptor family were over-represented among genes regulated by cAMP agonist/antagonist in patient T cells. CONCLUSIONS: Our data indicate that T cells from HIV-infected patients are in a pre-activated state and that a set of cytokine genes is hypo-responsive to activation and under tonic regulation by cAMP in these T cells.     

Tuberculosis in HIV-infected persons in the context of wide availability of highly active antiretroviral therapy.

Highly active antiretroviral therapy (HAART) greatly reduces the risk of developing tuberculosis for HIV-infected persons. Nonetheless, HIV-associated tuberculosis continues to occur in countries where HAART is widely used. To identify the characteristics of HIV-infected persons who develop tuberculosis in the context of the availability of HAART, the current authors analysed data taken from 271 patients diagnosed, in Italy, during 1999-2000. These patients represent 0.7% of the 40,413 HIV-infected patients cared for in the clinical units participating in this current study. From the data it was observed that 20 patients (7.4%) had a previous episode of tuberculosis whose treatment was not completed. Eighty-one patients (29.9%) were diagnosed with HIV at tuberculosis diagnosis, 108 (39.8%) were aware of their HIV status but were not on antiretroviral treatment and 82 (30.3%) were on antiretroviral treatment. Patients on antiretroviral treatment were significantly less immunosuppressed than patients with HIV diagnosed concurrently with tuberculosis, or other patients not on antiretrovirals (median CD4 lymphocytes count: 220 cells x mm(-3) versus 100 cells x mm(-3), and 109 cells x mm(-3), respectively). No significant differences in clinical presentation of tuberculosis according to antiretroviral therapy status were recorded. Failure of tuberculosis control interventions (e.g. noncompletion of treatment) and of HIV care (delayed diagnosis of HIV infection and suboptimal uptake of therapy) may contribute to continuing occurrence of HIV-associated tuberculosis in a country where highly active antiretroviral therapy is largely available. However, a significant proportion of cases occur in patients who are on antiretroviral treatment.     

Alcohol Consumption and HIV Disease Progression: Are They Related?

BACKGROUND: The relationship between alcohol consumption and HIV disease progression has received limited attention in the era of highly active antiretroviral therapy (HAART). METHODS: We assessed CD4 cell count, HIV RNA levels, and alcohol consumption in the past month, defined as none, moderate, and at risk, in 349 HIV-infected people with a history of alcohol problems. We investigated the relationship between alcohol consumption and HIV disease markers CD4 cell count and HIV RNA level, stratified by HAART use, using multivariable regression. RESULTS: No significant differences in CD4 cell count or HIV RNA level were found across the categories of alcohol consumption for patients who were not receiving HAART. However, among patients who were receiving HAART, log HIV RNA levels were significantly higher in those with moderate (2.17 copies/ml) and at-risk (2.73 copies/ml) alcohol use compared with none (1.73 copies/ml; p = 0.006). CD4 cell counts in those with moderate (368 cells/microl) and at-risk (360 cells/microl) alcohol use were lower than for subjects who reported none (426 cells/microl; p = 0.07). CONCLUSION: Among patients who have a history of alcohol problems and are receiving antiretroviral treatment, alcohol consumption was associated with higher HIV RNA levels and lower CD4 counts. No comparable association was found for similar patients who were not receiving HAART. Addressing alcohol use in HIV-infected patients, especially those who are receiving HAART, may have a substantial impact on HIV disease progression.     

Short communication: HIV infection, antiretrovirals, and apoptosis: studies on skeletal muscle

Increased apoptosis in CD4+ T lymphocytes plays an important role in the pathogenesis of HIV infection and it has also invoked some HIV-related as well as antiretroviral-related adverse events. We assessed whether increased apoptosis is also present in the skeletal muscle of HIV-infected patients. We included 36 consecutive individuals, 18 without (group A) and 18 with HIV infection. The latter group consisted of five asymptomatic antiretroviral-naive HIV-infected individuals (group B), six asymptomatic HIV-infected individuals on highly active antiretroviral therapy (HAART, group C), and seven HIV-infected individuals on HAART with lipodystrophy (group D). Immunohistochemical reaction using deoxyribonucleotidyltransferase-mediated- dUTP-biotin nick-end labeling (TUNEL) was performed on skeletal muscle samples. None of the uninfected patients (group A) showed data of increased apoptosis, while 16 out of 18 infected patients did (p < 0.001). All subgroups of infected subjects (groups B-D) showed a significant increase of apoptosis in TUNEL with respect to uninfected individuals, but the comparison between the different subgroups of infected patients did not reveal significant differences. We conclude that skeletal muscle of HIV-infected patients exhibits increased apoptosis compared with that of uninfected patients, but the role of HAART in inducing apoptosis remains to be established.     

Decreased expression of zeta molecules by T lymphocytes is correlated with disease progression in human immunodeficiency virus-infected persons.

In human immunodeficiency virus type 1 (HIV-1) infection, functional activities of T lymphocytes are impaired. Analogous to tumor-infiltrating T lymphocytes from cancer patients, in whom poor proliferative responses are associated with fewer zeta molecules, this study compared expression of CD3zeta molecules by T lymphocytes from HIV-infected persons and healthy controls. Flow cytometry and immunoblotting revealed significantly diminished zeta expression by CD3, CD4, and CD8 T lymphocytes from AIDS patients but not from persons without AIDS. zeta-mRNA levels were also decreased in cells from AIDS patients. CD3zeta expression correlated significantly with CD4 cell counts and HIV-1 RNA levels; impaired expression of CD3zeta molecules appeared to be reversible upon virus load reduction following highly active antiretroviral treatment (HAART). Thus, reduced expression of CD3zeta molecules by T lymphocytes from HIV-infected persons correlates with disease status. Investigations into CD3zeta expression by subpopulations of peripheral T lymphocytes and by T lymphocytes in lymphoid tissues will contribute to the understanding of immune reconstitution of HIV-infected patients following HAART.