Declining levels of rescued lymphoproliferative response to human cytomegalovirus (HCMV) in AIDS patients with or without HCMV disease following long-term HAART

The use of humoral responses as a marker of CMV burden in HIV patients on ART requires consideration of T-cell recovery and persistent B-cell activation

OBJECTIVES

Elevated humoral responses to cytomegalovirus (CMV) associate with increased risk of cardiovascular disease (CVD) in HIV patients on antiretroviral therapy (ART). To better understand the persistence of CMV humoral responses in relation to CVD, we determined trends in CMV antibody levels over the first 10 years on ART.

DESIGN

We describe longitudinal analyses of plasma from 13 HIV patients commencing ART with <210 CD4 T-cells/µL and 27 controls. Antibodies reactive with CMV (fibroblast lysate, gB and IE-1 antigens), EBV-VCA, and HIVgp41 were quantitated. B-cell activation was assessed via total IgG and sBAFF. Inflammation was assessed via sTNF-RI and sCD14.

RESULTS

Amongst CMV seropositive HIV patients, levels of antibody reactive with CMV (P = 0.03) and EBV-VCA (P = 0.02) peaked after 1 year on ART. Levels of total IgG, sCD14, and sTNF-RI declined to approximate those in controls after 10 years, but sBAFF (P = 0.0002), EBV-VCA (P = 0.001), and CMV (P = 0.0004) antibodies remained elevated. A strong correlation between sBAFF and CMVgB antibody was seen at 10 years (R = 0.93, P = 0.0009) and verified in a second cohort.

CONCLUSIONS

CMV antibody titres peak on ART and remain high. A correlation between CMV antibody and sBAFF suggests a role for HIV-induced B-cell pathology that may affect its use as a marker of CMV burden.

Restoration of CMV-specific-CD4 T cells with ART occurs early and is greater in those with more advanced immunodeficiency

Objectives

Restoration of Cytomegalovirus-specific-CD4 T cell (CMV-Sp-CD4) responses partly accounts for the reduction of CMV-disease with antiretroviral-therapy (ART), but CMV-Sp-CD4 may also drive immune activation and immunosenescence. This study characterized the dynamics of CMV-Sp-CD4 after ART initiation and explored associations with CD4 T cell recovery as well as frequency of naïve CD4 T cells at week 96.

Methods

Fifty HIV-infected, ART-naïve Thai adults with CD4 T cell count ≤350cells/µL and starting ART were evaluated over 96 weeks (ClinicalTrials.gov identifier NCT01296373). CMV-Sp-CD4 was detected by co-expression of CD25/CD134 by flow cytometry after CMV-antigen stimulation.

Results

All subjects were CMV sero-positive, 4 had quantifiable CMV-DNA (range 2.3-3.9 log₁₀ copies/mL) at baseline but none had clinically apparent CMV-disease. Baseline CMV-Sp-CD4 response was positive in 40 subjects. Those with CD4 T cell count <100cells/µL were less likely to have positive baseline CMV-Sp-CD4 response (P=0.003). Positive baseline CMV-Sp-CD4 response was associated with reduced odds of quantifiable CMV-DNA (P=0.022). Mean CD4 T cell increase at week 96 was 213 cells/µL. This was associated positively with baseline HIV-VL (P=0.001) and negatively with age (P=0.003). The frequency of CMV-Sp-CD4 increased at week 4 (P=0.008), then declined. Those with lower baseline CMV-Sp-CD4 (P=0.009) or CDC category C (P<0.001) had greater increases in CMV-Sp-CD4 at week 4. At week 96, CD4 T cell count was positively (P<0.001) and the frequency of CMV-Sp-CD4 was negatively (P=0.001) associated with the percentage of naïve CD4 T cells.

Conclusions

Increases in CMV-Sp-CD4 with ART occurred early and were greater in those with more advanced immunodeficiency. The frequency of CMV-Sp-CD4 was associated with reduced naïve CD4 T cells, a marker associated with immunosenescence.

Prevalence and clinical management of cytomegalovirus retinitis in AIDS patients in Shanghai, China

Background

Cytomegalovirus retinitis is a common AIDS-associated illness, leading to blindness in up to 30% of patients. This study was to investigate the prevalence and clinical management of the cytomegalovirus retinitis associated with AIDS in a large municipality of China.

Methods

Clinical and laboratory data from 23 cytomegalovirus retinitis patients (35 eyes) out of 303 hospitalized AIDS individuals in a single medical center were analyzed retrospectively. Two of 23 patients were diagnosed cytomegalovirus retinitis just before hospitalization without anti-CMV therapy. Ganciclovir combined with the high active anti-retroviral therapy was installed for treatment of cytomegalovirus retinitis after diagnosis was confirmed. The data were analyzed by specialists and statistics was also applied.

Results

The prevalence of cytomegalovirus retinitis in hospitalized AIDS patients was 7.6% in this study. The level of CD₄⁺ T lymphocytes was correlated well with the occurrence of cytomegalovirus retinitis, showing 16.8% (19/113) (95% confidence interval: 10.4,25.0), 5.4% (3/56) (95% confidence interval: 1.1,14.9), and 1.4% (1/69) (95% confidence interval: 0.0,7.8) occurrence in the patients with CD₄⁺ T lymphocyte counts < 50, 50~99, and 100~199 cells/μl, respectively. The mean CD₄⁺ T lymphocyte counts was 31.7 ± 38.6 cells/μl in 23 AIDS patients with cytomegalovirus retinitis. Median CD₄⁺ T lymphocyte count is 20 cells/μl with inter-quartile range as (5, 36). Seven patients died (11 eyes) and 16 patients (24 eyes) survived. The proportion of blindness and low vision in eyes infected with cytomegalovirus retinitis respectively was 20.8% (5/24) and 29.2% (7/24) when they were diagnosed in survivors. The ganciclovir therapy was effective in 16 patients (24 eyes). Clinical recovery of cytomegalovirus retinitis was 41.7% (10/24) and clinical improvement 58.3% (14/24). After anti-CMV treatment, the proportion of blindness or low vision was 16.7% (4/24).

Conclusions

The AIDS patients with CD₄⁺ T lymphocyte < 50 cells/μl had increased susceptibility to cytomegalovirus associated retinitis. Cytomegalovirus retinitis is a serious disease causing blindness. The cytomegalovirus retinitis in the AIDS patients was response well to ganciclovir therapy. We should check their eyes routinely such as dilated fundus examination with an indirect ophthalmoscope in the AIDS patients with CD₄⁺ T lymphocyte counts < 50 cells/μl.

The magnitude of interferon-gamma responses to human cytomegalovirus is predictive for HIV-1 disease progression

BACKGROUND

Human cytomegalovirus (HCMV) infection has been strongly associated to HIV-1 progression. We have investigated whether the magnitude of the overall peripheral blood mononuclear cell responses to HCMV stimulation correlated with HIV-1 progression.

METHODS

Blood samples were collected from 75 HIV-1-positive individuals on highly active antiretroviral therapy with CD4 count>500 cells per cubic millimeter and undetectable HIV RNA just before interrupting treatment. Specific interferon-gamma (IFN-gamma) HCMV cell responses were measured by an enzyme-linked immunospot (ELISPOT) assay. The results were analyzed by Kaplan-Meier survival curves, contingency tests, and the Cox proportional hazard models to evaluate the predictive value of peripheral blood responses to HCMV and the length of time that patients were off treatment.

RESULTS

Patients were stratified into those with weak (<500 spot-forming units) or strong (>500 spot-forming units) IFN-gamma responses to HCMV. During the 3-year follow-up, 51% of patients with strong responses remained untreated compared with 14% of patients with weak HCMV responses (P=0.0015). Length of time without therapy was also longer in patients with stronger responses (hazard ratio=2.08; P=0.001). HCMV responses were still predictive of restarting therapy after adjusting for the CD4 nadir counts.

CONCLUSION

Specific IFN-gamma responses to HCMV may be employed as a predictive useful marker for the evolution of HIV-1 infection.

Withdrawal of maintenance therapy for cytomegalovirus retinitis in AIDS patients exhibiting immunological response to HAART

BACKGROUND: Before the introduction of highly active antiretroviral therapy (HAART), CMV retinitis was a common complication in patients with advanced HIV disease and the therapy was well established; it consisted of an induction phase to control the infection with ganciclovir, followed by a lifelong maintenance phase to avoid or delay relapses. METHODS: To determine the safety of CMV maintenance therapy withdrawal in patients with immune recovery after HAART, 35 patients with treated CMV retinitis, on maintenance therapy, with CD4+ cell count greater than 100 cells/mm³ for at least three months, but almost all patients presented these values for more than six months and viral load < 30000 copies/mL, were prospectively evaluated for the recurrence of CMV disease. Maintenance therapy was withdrawal at inclusion, and patients were monitored for at least 48 weeks by clinical and ophthalmologic evaluations, and by determination of CMV viremia markers (antigenemia-pp65), CD4+/CD8+ counts and plasma HIV RNA levels. Lymphoproliferative assays were performed on 26/35 patients. RESULTS: From 35 patients included, only one had confirmed reactivation of CMV retinitis, at day 120 of follow-up. No patient returned positive antigenemia tests. No correlation between lymphoproliferative assays and CD4+ counts was observed. CONCLUSION: CMV retinitis maintenance therapy discontinuation is safe for those patients with quantitative immune recovery after HAART.

Deficient in vitro anti-mycobacterial immunity despite successful long-term highly active antiretroviral therapy in HIV-infected patients with past history of tuberculosis infection or disease

We evaluated the anti-Mycobacterium tuberculosis (Mtb) immune responses of HIV patients after long-term successful HAART, presenting >500 TCD4+ cells/microl, undetectable viral load, and past history of tuberculosis infection (HIV+PPD+, n=14) or disease (HIV+CTB, n=17). Their lymphoproliferative and IFN-gamma responses were compared with those from HIV-uninfected controls either PPD+ (HIV-PPD+, n=17) or with past history of pulmonary tuberculosis (n=15). Most HIV-infected patients presented normal PHA responses while responses to the Mtb recombinant polypeptides ESAT-6 and Ag85B were markedly reduced. Responses to a whole Mtb lysate (S-Mtb) in HIV+PPD+ patients were lower than in HIV-PPD+ controls, while in HIV+CTB patients these responses were similar to that of past-tuberculosis controls. Comparison between the two HIV groups also suggested better S-Mtb responses in those cured from tuberculosis. Thus, while immune responses to single Mtb proteins are depressed even after successful HAART, reactivity to S-Mtb is high, specially in those cured from tuberculosis, possibly as a result of the survival of higher numbers of mycobacteria-specific T cell clones during the immunosuppression phase, which may afford sufficient protection against new Mtb challenges.

CXCR4 or CCR5 tropism of human immunodeficiency virus type 1 isolates does not determine the immunological milieu in patients responding to antiretroviral therapy

Here we address whether CCR5 or CXCR4 tropism of the predominant viral strain detected before or on combination antiretroviral therapy (ART) explains why some human immunodeficiency virus (HIV)-infected patients who begin ART with advanced HIV disease retain low interferon (IFN)-gamma responses, despite recovery of CD4(+) T cell counts. Tropism was determined by culture and confirmed by gp120 V3 loop sequence of multiple plasma samples in eight adult male patients who began treatment with <50 CD4(+) T cells/microL. Four patients had mixed infections, one had only R5 HIV, and three had only X4 HIV. Of these, two carried CCR5Delta32. Viral tropism was not related to CD4(+) T cell counts or HIV RNA levels. When immunological responses were monitored over several years, IFN-gamma responses to cytomegalovirus were below the median value of uninfected controls and similar in patients with R5, X4, or mixed infection. Interleukin-5 responses were low and plasma soluble CD30 levels were high at treatment onset, but resolved with control of HIV replication irrespective of HIV tropism. Levels of LAG-3 (lymphocyte activation gene-3 protein) were elevated in patients with uncontrolled HIV replication. Hence the immunological milieu did not reflect HIV tropism.

Prospective simultaneous quantification of human cytomegalovirus-specific CD4+ and CD8+ T-cell reconstitution in young recipients of allogeneic hematopoietic stem cell transplants

We investigated immune reconstitution against human cytomegalovirus (HCMV) in 57 hematopoietic stem cell transplant (HSCT) recipients, aged 1 to 24 years, through a novel method combining T-cell stimulation by HCMV-infected autologous dendritic cells with simultaneous cytometric quantification of HCMV-specific, IFNgamma-producing CD4(+) and CD8(+) T cells. Lymphoproliferative response (LPR) to HCMV antigens was also determined. Patients were stratified into 2 groups according to HCMV serostatus, comprising 39 HCMV-seropositive (R(+)) and 18 HCMV-seronegative (R(-)) patients who received a transplant from a sero-positive donor. Recovery of both HCMV-specific CD4(+) and CD8(+) T-cell immunity occurred in all 39 R(+) patients within 6 months and in 6 (33%) of 18 R(-) patients within 12 months. In R(+) patients, the median numbers of HCMV-specific CD8(+) and CD4(+)T cells were significantly higher than those of healthy controls, starting from days +60 and +180, respectively. In (R-) patients, the median numbers of HCMV-specific T cells were consistently lower than in R(+) patients. LPR was delayed compared with reconstitution of IFNgamma-producing T cells. Patients with delayed specific immune reconstitution experienced recurrent episodes of HCMV infection. HCMV seropositivity of young HSCT recipients is the major factor responsible for HCMV-specific immune reconstitution, irrespective of donor serostatus, and measurement of HCMV-specific T cells appears useful for correct management of HCMV infection.

Interferon-Gamma Responses to Candida Recover Slowly or Remain Low in Immunodeficient HIV Patients Responding to ART

Extended assessments of memory T-cell responses in HIV patients who have a satisfactory virological response to combination antiretroviral therapy (CART) have been limited by availability of longitudinal samples and of antigens to which most individuals (including HIV-negative controls) have been exposed. Studies of cytomegalovirus (CMV) show that interferon-gamma (IFN-gamma) responses never recover completely, but this may be antigen-specific. Here we present responses to Candida and CMV antigens analyzed using a statistical approach that derives overall trends from samples collected at variable time points. Results were considered in relation to putative markers of T-regulatory cells. Blood mononuclear cells collected from seventeen HIV-1 patients (nadir <100 CD4 T cells/mL) 0-8 years after initiation of CART were stimulated with Candida spp lysate, Candida enolase protein or CMV lysate and production of IFN-gamma was assessed by ELISpot assay. CD4 T-cell counts increased fivefold and stabilized within 24 months on CART, following control of plasma viremia. IFN-gamma responses to Candida antigens began low and increased slowly, generating positive slope up to 60 months on CART (Candida enolase p=0.008; Candida lysate p=0.03; mixed-model Wald test). Only two patients displayed a CMV or Candida-specific IFN-gamma response above the median for seronegative controls. Proportions of T cells expressing CD25 or CD57 did not correlate with IFN-gamma responses. Slow reconstitution of IFN-gamma responses to CMV and Candida in previously immunodeficient patients with restored CD4+ T-cell counts on CART suggests a broad and nonresolving defect in memory T-cell responses.

Dendritic-cell infection by human cytomegalovirus is restricted to strains carrying functional UL131-128 genes and mediates efficient viral antigen presentation to CD8+ T cells

Human cytomegalovirus (HCMV) genetic determinants of endothelial-cell tropism and virus transfer to leukocytes (both polymorphonuclear and monocyte) have been recently identified in the UL131-128 genes. Here it is documented that the same genetic determinants of HCMV are responsible for monocyte-derived dendritic-cell (DC) tropism, i.e. all endotheliotropic and leukotropic strains of HCMV are also DC-tropic (or dendrotropic). In fact, all recent clinical HCMV isolates and deletion mutants sparing the UL131-128 locus as well as the endotheliotropic revertants AD169 and Towne were able to productively infect DC following co-culture with infected endothelial cells. On the contrary, the same clinical isolates extensively propagated in human fibroblasts, the UL131-128 deletion mutants and the reference laboratory strains were not. Peak extracellular virus titres in DC were reached 4-7 days post-infection (p.i.). Viral proteins pp65 and p72 were detected 1-3 h p.i., involving the great majority of DC 24 h p.i., while gB was abundantly detected 96 h p.i., when a cytopathic effect first appeared. Infection of DC with cell-free virus released into the medium could only be achieved with HCMV strains extensively adapted to growth in endothelial cells, reaching the peak titres 10 days p.i. DC infected for 24 h with cell-free virus and incubated for 16 h with autologous peripheral blood mononuclear cells were found to act as a potent stimulator of both HCMV-specific CD4+- and CD8+-mediated immune responses, as determined by cytokine flow cytometry. DC incubated with inactivated crude whole viral antigen preparations were only capable of eliciting a significant CD4+-mediated immune response.

Restoration of CD4 T-cell responses to cytomegalovirus is short-lived in severely immunodeficient HIV-infected patients responding to highly active antiretroviral therapy

OBJECTIVES

To define the level of pathogen-specific immune reconstitution persisting over 3 to 5 years of highly active antiretroviral therapy (HAART) in HIV-infected patients who began therapy with CD4 T-cell counts below 50 cells/microL.

METHODS

Cytomegalovirus (CMV)-specific T-cell responses were analysed in adult HIV-1-infected patients with nadir CD4 T-cell counts below 50 cells/microL before HAART. CMV-specific CD4 T-cell responses were measured by interferon-gamma enzyme-linked immunospot assay (ELISpot assay), lymphoproliferation and interferon-gamma levels in cell culture supernatants.

RESULTS

CD4 T-cell responses to CMV were low in untreated patients and remained low during the first year on HAART, but increased progressively to levels similar to those found in HIV-seronegative CMV-seropositive controls at 3 years. Responses then declined markedly and at 5 years were lower than controls. This could not be explained by changes in CD4 or CD8 T-cell counts or plasma HIV RNA levels. Interferon-gamma and interleukin-5 responses to a mitogen were maintained or elevated.

CONCLUSIONS

CMV-specific CD4 T-cell responses were found to decline after 3-5 years on HAART and may provide inadequate long-term protection against CMV disease in patients who are severely immunodeficient prior to treatment.

Assessment of human cytomegalovirus specific T cell immunity in human immunodeficiency virus infected patients in different disease stages following HAART and in long-term non-progressors

T cell immunity to human cytomegalovirus (HCMV) was assessed in HAART-treated HIV-1 infected patients (9 asymptomatic, CDC group A; and 22 symptomatic, CDC group B), and in eight HIV-1 long term non-progressors. Patients were either prospectively or cross-sectionally examined for CD4(+) T cell counts, HIV RNA load, HCMV leukoDNAemia, HCMV DNA in urine, lymphoproliferative response (LPR) to HCMV and phytohemagglutinin (PHA), and cytokine secretion (IFN-gamma and IL-4) by HCMV-stimulated peripheral blood mononuclear cell (PBMC) cultures. No patient either progressed to clinical AIDS or developed HCMV active infection during the study period. Twenty-nine patients responded to HAART, though 12 patients failed to recover the LPR to HCMV over the study period (three from CDC group A and nine from CDC group B). In contrast to healthy control individuals, most patients displaying positive LPRs LPRs to HCMV had unstable responses. Sustained LPRs to HCMV were significantly associated with high pre-HAART nadir CD4(+) T cell counts. Long-term suppression of HIV viremia correlated with recovery of LPR to HCMV. Sequential PBMC cultures from most patients secreted IFN-gamma (but not IL-4) at normal levels upon HCMV stimulation, irrespective of the pre-HAART nadir CD4(+) T cell counts and CDC group to which patients belonged. Failure to reconstitute IFN-gamma response was associated with very low pre-HAART nadir CD4(+) T cell counts. Control of HCMV infection in the cohort was associated with either recovery or maintenance of IFN-gamma response rather than with reconstitution of LPR to HCMV. A LPR to HCMV was absent in three out of eight long term non-progressors; contrarily, all patients showed preserved IFN-gamma responses.

Immune restoration disease after antiretroviral therapy

Suppression of HIV replication by highly active antiretroviral therapy (HAART) often restores protective pathogen-specific immune responses, but in some patients the restored immune response is immunopathological and causes disease [immune restoration disease (IRD)]. Infections by mycobacteria, cryptococci, herpesviruses, hepatitis B and C virus, and JC virus are the most common pathogens associated with infectious IRD. Sarcoid IRD and autoimmune IRD occur less commonly. Infectious IRD presenting during the first 3 months of therapy appears to reflect an immune response against an active (often quiescent) infection by opportunistic pathogens whereas late IRD may result from an immune response against the antigens of non-viable pathogens. Data on the immunopathogenesis of IRD is limited but it suggests that immunopathogenic mechanisms are determined by the pathogen. For example, mycobacterial IRD is associated with delayed-type hypersensitivity responses to mycobacterial antigens whereas there is evidence of a CD8 T-cell response in herpesvirus IRD. Furthermore, the association of different cytokine gene polymorphisms with mycobacterial or herpesvirus IRD provides evidence of different pathogenic mechanisms as well as indicating a genetic susceptibility to IRD. Differentiation of IRD from an opportunistic infection is important because IRD indicates a successful, albeit undesirable, effect of HAART. It is also important to differentiate IRD from drug toxicity to avoid unnecessary cessation of HAART. The management of IRD often requires the use of anti-microbial and/or anti-inflammatory therapy. Investigation of strategies to prevent IRD is a priority, particularly in developing countries, and requires the development of risk assessment methods and diagnostic criteria.

[Immune restoration inflammatory syndromes]

Increase of prevalence of certain immunodeficiencies is caused by more frequent use of immunosuppresive treatment, by advances in supportive care of immunodeficient individuals and by the pandemic spread of HIV-infection respectively. Highly active antiretroviral treatment (HAART) is able to reconstitute the impaired immunity in the HIV-infected individual and therefore to reduce morbidity and mortality. On the other hand paradoxical exacerbation of inflammatory or opportunistic diseases may develop during immunoreconstitution. By their distinct pathophysiological, clinical and therapeutic particularities these disease have been summarized as Immune Restoration Inflammatory Syndromes (IRIS). This review summarizes the variety of immunoreconstitution disorders and describes possible diagnostic pitfalls. Potential therapeutic options and an algorithm for the classification of the syndrome are proposed.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

HIV, 'an evolving species'. Roles of cellular activation and co-infections

Each small variation of the genome of a species can be preserved if it is useful for the survival of the species in a given environment. Within this framework, the finality of the biological cycle of HIV consists in a search for harmony (biological coherence) with man, which is to say a stable condition. Cellular activation appears to be the strategy developed by HIV in order to achieve this coherence. The price of this strategy is the AIDS. The first contact between HIV and immune system appears to determine the subsequent clinical outcome and the future of HIV. Lymphocytic activation varies during the course of the vital cycle of HIV. For each individual, this lymphocytic activation depends on both the HLA repertoire acquired during thymic ontogenesis and the antigenic experience before and after HIV infection. Thus intercurrent infections alter the immune condition of the organism and influence the outcome of HIV. We described a synthetic analysis of the effects of HIV on the surface protein expression and the cellular activation pathways which should provide insights in the evolutionary relationship between HIV and man and should permit to do a more physiological therapeutic approach.

Immune Restoration Inflammatory Syndromes: The Dark Side of Successful Antiretroviral Treatment

The prevalence of cellular immunodeficiency has increased due to rising use of immunosuppressive therapies and the pandemic spread of HIV infection. More recently, the introduction of highly active antiretroviral therapy (HAART) in HIV has led to significant immune reconstitution, even in patients with previously long-lasting secondary immunodeficiency. HAART reduces morbidity and mortality in HIV infection and also changes the clinical course of prevalent subclinical opportunistic infections or autoimmune diseases. Atypical inflammatory disorders develop after initiation of HAART and have been summarized as "immune reconstitution syndrome," "immune restoration disease," and "immune restoration inflammatory syndrome." However, diagnostic criteria and standards of therapy are yet to be defined. The awareness for these diseases is of increasing importance from a clinical point of view. This review summarizes the variety of immunoreconstitution disorders and describes possible diagnostic pitfalls. We also propose possible therapeutic options.

Partial restoration of cytokine profile despite reconstitution of cytomegalovirus-specific cell-mediated immunity in human immunodeficiency virus-infected patients during highly active antiretroviral treatment

We reconstituted cytomegalovirus (CMV)-specific T-cell responses in human immunodeficiency virus-1-positive, CMV-positive patients receiving highly active antiretroviral treatment (HAART). We used several combinations of functionality parameters to determine the degree of T-lymphocyte reconstitution obtained during 1 year of treatment. Untreated patients displayed CMV-specific cytotoxic T-lymphocyte (CTL) activity despite the absence of CMV-specific lymphoproliferative responses (LPRs) and despite the fact that interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) were not secreted. The absence of LPRs, IFN-gamma and IL-2 before antiretroviral treatment suggests that CMV-specific immunity was deregulated despite the high CD4+ T-cell counts presented by our cohort, which are critical to the reactivation of CMV disease. After 6 months of HAART, CTL activity had increased compared with the baseline, as had the levels of secreted IFN-gamma and LPR. However, the levels of specific IL-2 produced did not change during therapy, and no specific IL-2 was detected during the follow-up period. Taken together, our findings suggest that 1 year of HAART led to the recovery of some, but not all, CMV-specific responses in our cohort of patients.