Immunological and virological responses in HIV-1-infected adults at early stage of established infection treated with highly active antiretroviral therapy

People With Human Immunodeficiency Virus Receiving Suppressive Antiretroviral Therapy Show Typical Antibody Durability After Dual Coronavirus Disease 2019 Vaccination and Strong Third Dose Responses

BACKGROUND

Longer-term humoral responses to 2-dose coronavirus disease 2019 (COVID-19) vaccines remain incompletely characterized in people living with human immunodeficiency virus (HIV) (PLWH), as do initial responses to a third dose.

METHODS

We measured antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, angiotensin-converting enzyme 2 (ACE2) displacement, and viral neutralization against wild-type and Omicron strains up to 6 months after 2-dose vaccination, and 1 month after the third dose, in 99 PLWH receiving suppressive antiretroviral therapy and 152 controls.

RESULTS

Although humoral responses naturally decline after 2-dose vaccination, we found no evidence of lower antibody concentrations or faster rates of antibody decline in PLWH compared with controls after accounting for sociodemographic, health, and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after 2 doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though Omicron-specific responses were consistently weaker than responses against wild-type virus. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses.

CONCLUSION

PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after 2- and 3-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

SARS-CoV-2 immunity and vaccine strategies in people with HIV

Current severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines, based on the ancestral Wuhan strain, were developed rapidly to meet the needs of a devastating global pandemic. People living with Human Immunodeficiency Virus (PLWH) have been designated as a priority group for SARS-CoV-2 vaccination in most regions and varying primary courses (two- or three-dose schedule) and additional boosters are recommended depending on current CD4+ T cell count and/or detectable HIV viraemia. From the current published data, licensed vaccines are safe for PLWH, and stimulate robust responses to vaccination in those well controlled on antiretroviral therapy and with high CD4+ T cell counts. Data on vaccine efficacy and immunogenicity remain, however, scarce in PLWH, especially in people with advanced disease. A greater concern is a potentially diminished immune response to the primary course and subsequent boosters, as well as an attenuated magnitude and durability of protective immune responses. A detailed understanding of the breadth and durability of humoral and T cell responses to vaccination, and the boosting effects of natural immunity to SARS-CoV-2, in more diverse populations of PLWH with a spectrum of HIV-related immunosuppression is therefore critical. This article summarizes focused studies of humoral and cellular responses to SARS-CoV-2 infection in PLWH and provides a comprehensive review of the emerging literature on SARS-CoV-2 vaccine responses. Emphasis is placed on the potential effect of HIV-related factors and presence of co-morbidities modulating responses to SARS-CoV-2 vaccination, and the remaining challenges informing the optimal vaccination strategy to elicit enduring responses against existing and emerging variants in PLWH.

People with HIV receiving suppressive antiretroviral therapy show typical antibody durability after dual COVID-19 vaccination, and strong third dose responses

Background:

Longer-term humoral responses to two-dose COVID-19 vaccines remain incompletely characterized in people living with HIV (PLWH), as do initial responses to a third dose.

Methods:

We measured antibodies against the SARS-CoV-2 spike protein receptor-binding domain, ACE2 displacement and viral neutralization against wild-type and Omicron strains up to six months following two-dose vaccination, and one month following the third dose, in 99 PLWH receiving suppressive antiretroviral therapy, and 152 controls.

Results:

Though humoral responses naturally decline following two-dose vaccination, we found no evidence of lower antibody concentrations nor faster rates of antibody decline in PLWH compared to controls after accounting for sociodemographic, health and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after two doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though anti-Omicron responses were consistently weaker than against wild-type. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses.

Conclusion:

PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after two- and three-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

Humoral immune responses to COVID-19 vaccination in people living with HIV receiving suppressive antiretroviral therapy

Humoral responses to COVID-19 vaccines in people living with HIV (PLWH) remain incompletely characterized. We measured circulating antibodies against the SARS-CoV-2 spike protein receptor-binding domain (RBD), ACE2 displacement and viral neutralization activities one month following the first and second COVID-19 vaccine doses, and again 3 months following the second dose, in 100 adult PLWH and 152 controls. All PLWH were receiving suppressive antiretroviral therapy, with median CD4+ T-cell counts of 710 (IQR 525-935) cells/mm3, though nadir CD4+ T-cell counts ranged as low as <10 cells/mm3. After adjustment for sociodemographic, health and vaccine-related variables, HIV infection was associated with lower anti-RBD antibody concentrations and ACE2 displacement activity after one vaccine dose. Following two doses however, HIV was not significantly associated with the magnitude of any humoral response after multivariable adjustment. Rather, older age, a higher burden of chronic health conditions, and dual ChAdOx1 vaccination were associated with lower responses after two vaccine doses. No significant correlation was observed between recent or nadir CD4+ T-cell counts and responses to two vaccine doses in PLWH. These results indicate that PLWH with well-controlled viral loads and CD4+ T-cell counts in a healthy range generally mount strong initial humoral responses to dual COVID-19 vaccination. Factors including age, co-morbidities, vaccine brand, response durability and the rise of new SARS-CoV-2 variants will influence when PLWH will benefit from additional doses. Further studies of PLWH who are not receiving antiretroviral treatment or who have low CD4+ T-cell counts are needed, as are longer-term assessments of response durability.

Humoral immune responses to COVID-19 vaccination in people living with HIV receiving suppressive antiretroviral therapy

Humoral responses to COVID-19 vaccines in people living with HIV (PLWH) remain incompletely understood. We measured circulating antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, ACE2 displacement and live viral neutralization activities one month following the first and second COVID-19 vaccine doses in 100 adult PLWH and 152 controls. All PLWH were receiving suppressive antiretroviral therapy, with median CD4+ T-cell counts of 710 (IQR 525-935) cells/mm 3 . Nadir CD4+ T-cell counts ranged as low as <10 (median 280; IQR 120-490) cells/mm 3 . After adjustment for sociodemographic, health and vaccine-related variables, HIV infection was significantly associated with 0.2 log 10 lower anti-RBD antibody concentrations (p=0.03) and ∼11% lower ACE2 displacement activity (p=0.02), but not lower viral neutralization (p=0.1) after one vaccine dose. Following two doses however, HIV was no longer significantly associated with the magnitude of any response measured. Rather, older age, a higher burden of chronic health conditions, and having received two ChAdOx1 doses (versus a heterologous or dual mRNA vaccine regimen) were independently associated with lower responses. After two vaccine doses, no significant correlation was observed between the most recent or nadir CD4+ T-cell counts and vaccine responses in PLWH. These results suggest that PLWH with well-controlled viral loads on antiretroviral therapy and CD4+ T-cell counts in a healthy range will generally not require a third COVID-19 vaccine dose as part of their initial immunization series, though other factors such as older age, co-morbidities, vaccine regimen type, and durability of vaccine responses will influence when this group may benefit from additional doses. Further studies of PLWH who are not receiving antiretroviral treatment and/or who have low CD4+ T-cell counts are needed.

Extremely low viral reservoir in treated chronically HIV-1-infected individuals

BACKGROUND

Small viral reservoirs are found predominantly in HIV-1 controllers and individuals treated during acute/early HIV-1 infection. However, other HIV⁺ individuals could naturally also harbour low viral reservoirs.

METHODS

We screened 451 HIV-1-infected treated-individuals with suppressed plasma viremia for at least 3 years and stored cryopreserved peripheral blood mononuclear cells (PBMCs). Total HIV-DNA was analysed in PBMCs with ddPCR. Individuals with <50 HIV-DNA copies/10⁶ PBMCs constitute the 'Low Viral Reservoir Treated' cohort (LoViReT). Longitudinal samples were obtained from 12 chronically treated LoViReT and compared to 13 controls (>50 HIV-DNA copies/10⁶ PBMCs) to analyse total HIV-DNA, T-cell and NK-cell populations, HIV-1 specific antibodies, and plasma inflammation markers.

FINDINGS

We found that 9.3% of the individuals screened had <50 HIV-DNA copies/10⁶ PBMCs. At least 66% initiated cART during the chronic phase of HIV-1 infection (cp-LoViReT). Cp-LoViReT harboured lower levels of HIV-DNA before cART and after treatment introduction the decays were greater compared to controls. They displayed a marked decline in quantity and avidity in HIV-specific antibodies after initiation of cART. Cp-LoViReT had fewer CD8⁺ T_TM and T_EMRA in the absence of cART, and higher CD8⁺ T_N after 18 months on therapy.

INTERPRETATION

Treated chronically HIV-1-infected LoViReT represent a new phenotype of individuals characterized by an intrinsically reduced viral reservoir, less impaired CD8⁺ T-cell compartment before cART, and low circulating HIV-1 antigens despite being treated in the chronic phase of infection. The identification of this unique group of individuals is of great interest for the design of future eradication studies.

FUNDING

MSD Spain.

Lower Baseline Germinal Center Activity and Preserved Th1 Immunity Are Associated With Hepatitis B Vaccine Response in Treated HIV Infection

BACKGROUND

Why HIV-infected individuals have poor responses to standard dose and schedule hepatitis B virus immunization is not well understood.

METHODS

We compared the serologic and cellular immune profiles of treated HIV-infected individuals with similar durations of infection and preserved CD4 counts (> 350 cells/microliter) by hepatitis B vaccine (HBV) response before and after vaccination.

RESULTS

Similar levels of immune activation and plasma cytokine profile were found between non-responders and responders. The baseline plasma levels of CXCL-13, a surrogate of germinal center reactivity, were significantly lower in HBV responders compared to HBV non-responders and were a predictor of both vaccine response and titer. Furthermore, response to HBV vaccination was associated with a significantly higher frequency of circulating IgG^high memory B cells post vaccination and preserved Th1 antigen-specific T-cell responses.

CONCLUSIONS

Taken together, our data suggest that preserved Th1 responses are associated with hepatitis B vaccine response in treated HIV infection.

Long-term immune and virological response in HIV-infected patients receiving antiretroviral therapy

WHAT IS KNOWN AND OBJECTIVE

The trajectory of HIV viral load and CD4 count and the occurrence of clinical events are primary considerations in the evaluation of antiretroviral therapy (ART) success or failure, yet a large number of studies do not describe these events from the point of therapy initiation. This study aims to describe the virological and immune response to ART and factors associated with immune and virological success in outpatients from a HIV/AIDS clinic in southern Brazil from therapy initiation.

METHODS

Longitudinal observational with ambidirectional data collection study with adult patients followed for at least 12 months after enrolment. Outcomes include (i) favourable immune response, defined as CD4 count ≥200 cells/mm³; and (ii) virological success, defined as viral load below the limit of detection (50 copies/mL).

RESULTS

The study included 332 patients, mostly men (63%), whose mean age was 40 (±10) years and with median family income of BR$ 490·00 per month (IQR: 350-875). Before starting ART, 43% of patients had indications of stable immune status (CD4 count ≥200 cells/mm³); the median CD4 count was 179 cells/mm³ (IQR: 93·5, 267) and increased to 379·5 cells/mm³ (IQR: 236·5, 591·3). The proportion of patients with CD4 count ≥200 cells/mm³ increased from 76% to 83%, and with undetectable viral load (UVL) increased from 51·7% to 73%. Factors associated with immune success at the end of study follow-up were as follows: female gender, pretreatment CD4 count ≥200 cells/mm³, previous UVL (measured when started prospective follow-up) and treatment with three drugs compared with ≥4. Factors associated with virological success were as follows: UVL (measured when started prospective follow-up) and use of three drugs compared with ≥4.

WHAT IS NEW AND CONCLUSIONS

Results of this study show that a large proportion (73%) of patients have rapid and successful immune and virological responses to ART and that factors which predict this response include starting ART early, whereas viral load is low and CD4 count is high, with fewer drugs. These results further support the ongoing need for ongoing programmes to increase early HIV testing, early linkage to and treatment with ART, and increased viral suppression.

Recent trends in early stage response to combination antiretroviral therapy in Australia

BACKGROUND

There have been improvements in combination antiretroviral therapy (cART) over the past 15 years. The aim of this analysis was to assess whether improvements in ART have resulted in improvements in surrogates of HIV outcome.

METHODS

Patients in the Australian HIV Observational Database who initiated treatment using mono/duo therapy prior to 1996, or using cART from 1996 onwards, were included in the analysis. Patients were stratified by era of ART initiation. Median changes in CD4(+) T-cell count and the proportion of patients with detectable HIV viral load (>400 copies/ml) were calculated over the first 4 years of treatment. Probabilities of treatment switch were estimated using the Kaplan-Meier method.

RESULTS

A total of 2,753 patients were included in the analysis: 28% initiated treatment <1996 using mono/duo therapy and 72% initiated treatment ≥1996 using cART (30% 1996-1999, 12% 2000-2003, 11% 2004-2007 and 19% ≥2008). Overall CD4(+) T-cell count response improved by later era of initiation (P<0.001), although 2000-2003 CD4(+) T-cell count response was less than that for 1996-1999 (P=0.007). The average proportion with detectable viral load from 2 to 4 years post-treatment commencement by era was: <1996 mono/duo 0.69 (0.67-0.71), 1996-1999 cART 0.29 (0.28-0.30), 2000-2003 cART 0.22 (0.20-0.24), 2004-2007 cART 0.09 (0.07-0.10) and ≥2008 cART 0.04 (0.03-0.05). Probability of treatment switch at 4 years after initiation decreased from 53% in 1996-1999 to 29% after 2008 (P<0.001).

CONCLUSIONS

Across the five time-periods examined, there have been incremental improvements for patients initiated on cART, as measured by overall response (viral load and CD4(+) T-cell count) and also increased durability of first-line ART regimens.

Rapid perturbation in viremia levels drives increases in functional avidity of HIV-specific CD8 T cells

The factors determining the functional avidity and its relationship with the broad heterogeneity of antiviral T cell responses remain partially understood. We investigated HIV-specific CD8 T cell responses in 85 patients with primary HIV infection (PHI) or chronic (progressive and non-progressive) infection. The functional avidity of HIV-specific CD8 T cells was not different between patients with progressive and non-progressive chronic infection. However, it was significantly lower in PHI patients at the time of diagnosis of acute infection and after control of virus replication following one year of successful antiretroviral therapy. High-avidity HIV-specific CD8 T cells expressed lower levels of CD27 and CD28 and were enriched in cells with an exhausted phenotype, i.e. co-expressing PD-1/2B4/CD160. Of note, a significant increase in the functional avidity of HIV-specific CD8 T cells occurred in early-treated PHI patients experiencing a virus rebound after spontaneous treatment interruption. This increase in functional avidity was associated with the accumulation of PD-1/2B4/CD160 positive cells, loss of polyfunctionality and increased TCR renewal. The increased TCR renewal may provide the mechanistic basis for the generation of high-avidity HIV-specific CD8 T cells. These results provide insights on the relationships between functional avidity, viremia, T-cell exhaustion and TCR renewal of antiviral CD8 T cell responses.

CD8 T cells directed against virus are complex and functionally heterogeneous. One relevant component of CD8 T cells is their functional avidity which reflects their sensitivity to cognate antigens, i.e. how prone T cells are to respond when they encounter low doses of antigens. In patients with chronic and established HIV infection, we observed that the sensitivity of HIV-specific CD8 T cells was not different between patients with progressive or non-progressive disease. In contrast, the sensitivity of HIV-specific CD8 T cells was significantly lower in patients with early and recent HIV infection. Furthermore, CD8 T cells of high avidity were preferentially associated with a state of functional impairment known as exhaustion. Of interest, some patients treated with antiretroviral therapy during acute infection spontaneously interrupted their treatment and experienced a rebound of virus. In these patients, the avidity of HIV-specific CD8 T cells increased and this increase was associated to stronger cell exhaustion and greater renewal of the population of antiviral CD8 T cells, thus potentially providing the mechanistic basis for the generation of high-avidity CD8 T cells. Overall, our data suggest that rapid perturbation in viremia levels drove increases in the functional avidity of HIV-specific CD8 T cells.

Lymphoid Proliferations Associated With Human Immunodeficiency Virus Infection

Context.—Individuals who are immune deficient are at an increased risk for developing lymphoproliferative lesions and lymphomas. Human immunodeficiency virus (HIV) infection is 1 of 4 clinical settings associated with immunodeficiency recognized by the World Health Organization (WHO) in which there is an increased incidence of lymphoma and other lymphoproliferative disorders.

Objectives.—To describe the major categories of benign lymphoid proliferations, including progressive HIV-related lymphadenopathy, benign lymphoepithelial cystic lesions, and multicentric Castleman disease, as well as the different types of HIV-related lymphomas as defined by the WHO. The characteristic morphologic, immunophenotypic, and genetic features of the different entities will be discussed in addition to some of the pathogenetic mechanisms.

Data Sources.—The WHO classification of tumors of hematopoietic and lymphoid tissues (2001 and 2008), published literature from PubMed (National Library of Medicine), published textbooks, and primary material from the authors' current and previous institutions.

Conclusions.—HIV infection represents one of the clinical settings recognized by the WHO in which immunodeficiency-related lymphoproliferative disorders may arise. Although most lymphomas that arise in patients with HIV infection are diffuse, aggressive B-cell lesions, other lesions, which are “benign” lymphoid proliferations, may also be associated with significant clinical consequences. These lymphoproliferations, like many other immunodeficiency-associated lymphoproliferative disorders, are often difficult to classify. Studies of HIV-associated lymphoid proliferations will continue to increase our understanding of both the immune system and lymphomagenesis.

Rapid turnover of 2-LTR HIV-1 DNA during early stage of highly active antiretroviral therapy

Background

Despite prolonged treatment with highly active antiretroviral therapy (HAART), the infectious HIV-1 continues to replicate and resides latently in the resting memory CD4+ T lymphocytes, which blocks the eradication of HIV-1. The viral persistence of HIV-1 is mainly caused by its proviral DNA being either linear nonintegrated, circular nonintegrated, or integrated. Previous reports have largely focused on the dynamics of HIV-1 DNA from the samples collected with relatively long time intervals during the process of disease and HAART treatment, which may have missed the intricate changes during the intervals in early treatment.

Methodology/Principal Findings

In this study, we investigated the dynamics of HIV-1 DNA in patients during the early phase of HARRT treatment. Using optimized real time PCR, we observed significant changes in 2-LTR during the first 12-week of treatment, while total and integrated HIV-1 DNA remained stable. The doubling time and half-life of 2-LTR were not correlated with the baseline and the rate of changes in plasma viral load and various CD4+ T-cell populations. Longitudinal analyses on 2-LTR sequences and plasma lipopolysaccharide (LPS) levels did not reveal any significant changes in the same treatment period.

Conclusions/Significance

Our study revealed the rapid changes in 2-LTR concentration in a relatively large number of patients during the early HAART treatment. The rapid changes indicate the rapid infusion and clearance of cells bearing 2-LTR in the peripheral blood. Those changes are not expected to be caused by the blocking of viral integration, as our study did not include the integrase inhibitor raltegravir. Our study helps better understand the dynamics of HIV-DNA and its potential role as a biomarker for the diseases and for the treatment efficacy of HAART.

Proliferation capacity and cytotoxic activity are mediated by functionally and phenotypically distinct virus-specific CD8 T cells defined by interleukin-7R{alpha} (CD127) and perforin expression

Cytotoxicity and proliferation capacity are key functions of antiviral CD8 T cells. In the present study, we investigated a series of markers to define these functions in virus-specific CD8 T cells. We provide evidence that there is a lack of coexpression of perforin and CD127 in human CD8 T cells. CD127 expression on virus-specific CD8 T cells correlated positively with proliferation capacity and negatively with perforin expression and cytotoxicity. Influenza virus-, cytomegalovirus-, and Epstein-Barr virus/human immunodeficiency virus type 1-specific CD8 T cells were predominantly composed of CD127(+) perforin(-)/CD127(-) perforin(+), and CD127(-)/perforin(-) CD8 T cells, respectively. CD127(-)/perforin(-) and CD127(-)/perforin(+) cells expressed significantly more PD-1 and CD57, respectively. Consistently, intracellular cytokine (gamma interferon, tumor necrosis factor alpha, and interleukin-2 [IL-2]) responses combined to perforin detection confirmed that virus-specific CD8 T cells were mostly composed of either perforin(+)/IL-2(-) or perforin(-)/IL-2(+) cells. In addition, perforin expression and IL-2 secretion were negatively correlated in virus-specific CD8 T cells (P < 0.01). As previously shown for perforin, changes in antigen exposure modulated also CD127 expression. Based on the above results, proliferating (CD127(+)/IL-2-secreting) and cytotoxic (perforin(+)) CD8 T cells were contained within phenotypically distinct T-cell populations at different stages of activation or differentiation and showed different levels of exhaustion and senescence. Furthermore, the composition of proliferating and cytotoxic CD8 T cells for a given antiviral CD8 T-cell population appeared to be influenced by antigen exposure. These results advance our understanding of the relationship between cytotoxicity, proliferation capacity, the levels of senescence and exhaustion, and antigen exposure of antiviral memory CD8 T cells.

Long sequence duplications, repeats, and palindromes in HIV-1 gp120: length variation in V4 as the product of misalignment mechanism

We have shown that indels in gp120 V4 are associated to the presence of duplicated and palindromic sequences, suggesting that they may be produced by strand-slippage misalignment mechanism. Indels in V4 involved region-specific duplications 9 to 15 bp long, and repeats of various lengths, associated to trinucleotides AAT. No duplications were found in V3 and C3. The frequency of palindromic sequences in individual genes was found to be significantly higher in gp120 (p < or = 3.00E-7), and significantly lower in Tat (p < or = 9.00E-7) than the average frequency calculated over the full genome. The finding of elements of misalignment in association with indels in V4 suggests that these mutations may occur in proviral DNA after integration of HIV into the host genome. It also implies that occurrence of large indels in gp120 is not random but is directed by the presence and distribution of elements of misalignment in the HIV genome.

Quality of life and social support among patients receiving antiretroviral therapy in Western Uganda

Quality of life (QOL) among patients with HIV/AIDS has been shown to improve once treatment with antiretroviral therapy (ART) has been initiated. We conducted a cross-sectional study in Western Uganda to examine the factors associated with QOL among patients who had received ART for the duration of at least six months. We interviewed 330 patients attending the HIV/AIDS clinic at two government-supported hospitals in Western Uganda. We measured QOL using a culturally adapted version of the Medical Outcomes Study (MOS-HIV) tool and calculated the physical health summary (PHS) and mental health summary (MHS) scores. In addition, data were collected on sociodemographic factors, three-day self-reported adherence, social support, sexual behavior, CD4 count and viral load. Informational social support was significantly positively correlated with PHS (p=0.001) and MHS (p=0.002). Affectionate support was also significantly positively correlated to PHS (p=0.05) and MHS (p=0.03) but tangible support was not (PHS p value=0.85 and MHS p value=0.31). In the univariate analysis, older age, rural dwelling, alcohol use, CD4 count less than 200, and ART duration of less than one year were significantly associated with lower PHS scores. Lower PHS scores were also associated with sexual inactivity. In multivariate analysis, higher scores on informational social support and CD4> or =200 were associated with higher PHS score and past or recent alcohol consumption was associated with lower scores on MHS. Optimizing ART to restore CD4 count and provision of informational and affectionate social support but not tangible support, to HIV/AIDS patients may improve their QOL.

Influence of antiretroviral therapy on programmed death-1 (CD279) expression on T cells in lymph nodes of human immunodeficiency virus-infected individuals

Human immunodeficiency virus infection leads to T-cell exhaustion and involution of lymphoid tissue. Recently, the programmed death-1 pathway was found to be crucial for virus-specific T-cell exhaustion during human immunodeficiency virus infection. Programmed death-1 expression was elevated on human immunodeficiency virus-specific peripheral blood CD8+ and CD4+ T cells and correlated with disease severity. During human immunodeficiency infection, lymphoid tissue acts as a major viral reservoir and is an important site for viral replication, but it is also essential for regulatory processes important for immune recovery. We compared programmed death-1 expression in 2 consecutive inguinal lymph nodes of 14 patients, excised before antiretroviral therapy (antiretroviral therapy as of 1997-1999) and 16 to 20 months under antiretroviral therapy. In analogy to lymph nodes of human immunodeficiency virus-negative individuals, in all treated patients, the germinal center area decreased, whereas the number of germinal centers did not significantly change. Programmed death-1 expression was mostly found in germinal centers. The absolute extent of programmed death 1 expression per section was not significantly altered after antiretroviral therapy resulting in a significant-relative increase of programmed death 1 per shrunken germinal center. In colocalization studies, CD45R0+ cells that include helper/inducer T cells strongly expressed programmed death-1 before and during therapy, whereas CD8+ T cells, fewer in numbers, showed a weak expression for programmed death-1. Thus, although antiretroviral therapy seems to reduce the number of programmed death-1-positive CD8+ T lymphocytes within germinal centers, it does not down-regulate programmed death-1 expression on the helper/inducer T-cell subset that may remain exhausted and therefore unable to trigger immune recovery.

Distinct profiles of cytotoxic granules in memory CD8 T cells correlate with function, differentiation stage, and antigen exposure

Cytotoxic CD8 T cells exert their antiviral and antitumor activity primarily through the secretion of cytotoxic granules. Degranulation activity and cytotoxic granules (perforin plus granzymes) generally define CD8 T cells with cytotoxic function. In this study, we have investigated the expression of granzyme K (GrmK) in comparison to that of GrmA, GrmB, and perforin. The expression of the cytotoxic granules was assessed in virus-specific CD8 T cells specific to influenza virus, Epstein-Barr virus (EBV), cytomegalovirus (CMV), or human immunodeficiency virus type 1 (HIV-1). We observed a dichotomy between GrmK and perforin expression in virus-specific CD8 T cells. The profile in influenza virus-specific CD8 T cells was perforin(-) GrmB(-) GrmA(+/-) GrmK(+); in CMV-specific cells, it was perforin(+) GrmB(+) GrmA(+) GrmK(-/+); and in EBV- and HIV-1-specific cells, it was perforin(-/+) GrmB(+) GrmA(+) GrmK(+). On the basis of the delineation of memory and effector CD8 T cells with CD45RA and CD127, the GrmK(+) profile was associated with early-stage memory CD8 T-cell differentiation, the perforin(+) GrmB(+) GrmA(+) profile with advanced-stage differentiation, and the GrmB(+) GrmA(+) Grmk(+) profile with intermediate-stage differentiation. Furthermore, perforin and GrmB but not GrmA and GrmK correlated with cytotoxic activity. Finally, changes in antigen exposure in vitro and in vivo during primary HIV-1 infection and vaccination modulated cytotoxic granule profiles. These results advance our understanding of the relationship between distinct profiles of cytotoxic granules in memory CD8 T cells and function, differentiation stage, and antigen exposure.

The polymorphic nature of HIV type 1 env V4 affects the patterns of potential N-glycosylation sites in proviral DNA at the intrahost level

We have previously shown that env V4 from HIV-1 plasma RNA is highly heterogeneous within a single patient, due to indel-associated polymorphism. In this study, we have analyzed the variability of V4 in proviral DNA from unfractionated PBMC and sorted T and non-T cell populations within individual patients. Our data show that the degree of sequence variability and length polymorphism in V4 from HIV provirus is even higher than we previously reported in plasma. The data also show that the sequence of V4 depends largely on the experimental approach chosen. We could observe no clear trend for compartmentalization of V4 variants in specific cell types. Of interest is the fact that some variants that had been found to be predominant in plasma were not detected in any of the cell subsets analyzed. Consistently with our observations in plasma, V3 was found to be relatively conserved at both interpatient and intrapatient level. Our data show that V4 polymorphism involving insertions and deletions in addition to point mutations results in changes in the patterns of sequons in HIV-1 proviral DNA as well as in plasma RNA. These rearrangements may result in the coexistence, within the same individual, of a swarm of different V4 regions, each characterized by a different carbohydrate surface shield. Further studies are needed to investigate the mechanism responsible for the variability observed in V4 and its role in HIV pathogenesis.

Independent evolution of hypervariable regions of HIV-1 gp120: V4 as a swarm of N-Linked glycosylation variants

In this study we have characterized intra-patient length polymorphism in V4 by cloning and sequencing a C2-C4 fragment from HIV plasma RNA in patients at different stages of HIV disease. Clonal analysis of clade B, G, and CRF02 isolates during early infection shows extensive intra-patient V4 variability, due to the presence of indel-associated polymorphism. Indels, coupled to amino acid substitution events, affect the number and distribution of potential N-glycosylation sites, resulting in the coexistence, within the same patient, of V4 subsets, each characterized by different sizes, amino acid sequences, and potential N-glycosylation patterns. In contrast, V3 appears to be relatively homogeneous, with similar V3 associated to significantly different V4 within the same clinical specimen. Based on these data, we propose that during early chronic infection V4 is present as a highly divergent quasispecies, enabling the virus to adopt different conformational structures according to immune constrains and other selective pressures.

Oral lesions among persons with HIV disease with and without highly active antiretroviral therapy in southern India

BACKGROUND

The advent of highly active antiretroviral therapy (HAART) has changed the scenario of human immunodeficiency virus (HIV) infection. HIV patients in India have now access to generic HAART and this is the first report describing oral lesions in patients on HAART from our country.

METHODS

Oral lesions were studied in HIV seropositive patients (n = 50 on HAART and n = 50 not on HAART) attending a tertiary HIV referral care centre in India and patients on HAART were followed up.

RESULTS

There was a difference in the occurrence of oral candidiasis (OC) between HAART and non-HAART participants (8%, 24%; P < 0.05). Pseudomembranous candidiasis was 4% and 18% in HAART and non-HAART groups respectively (P < 0.05). In patients with CD4 count <or=200, OC was 5.6% in the HAART group and 39.1% in the non-HAART group (P < 0.05). Among patients with CD4 count >200, pigmentation was 43.8% in the HAART group and 14.8% in the non-HAART group (P < 0.05).

CONCLUSION

The prevalence of OC in patients who had access to HAART was less when compared with those who did not have access to HAART.

Functional signatures of protective antiviral T-cell immunity in human virus infections

The most common human viruses have different abilities to establish persistent chronic infection. Virus-specific T-cell responses are critical in the control of virus replication and in the prevention of disease in chronic infection. A large number of phenotypic markers and a series of functions have been used to characterize virus-specific CD4+ and CD8+ T-cell responses, and these studies have shown great phenotypic and functional heterogeneity of the T-cell responses against different viruses. The heterogeneity of the T-cell response has been proposed to be specific to each virus. However, over the past 2 years, several studies have provided evidence that the phenotypic and functional heterogeneity of CD4+ and CD8+ T-cell responses is predominantly regulated by the levels of antigen load. The levels of antigen load modulate the phenotypic and functional patterns of the T-cell response within the same virus infection. Furthermore, the functional characterization of virus-specific CD4+ and CD8+ T-cell responses has identified signatures of protective antiviral immunity. Polyfunctional, i.e. interleukin-2 and interferon-gamma (IFN-gamma) secretion and proliferation, and not monofunctional, i.e. IFN-gamma secretion, CD4+ and CD8+ T-cell responses represent correlates of protective antiviral immunity in chronic virus infections.

Presence of distinct subsets of cytolytic CD8+ T cells in chronic HIV infection

Cytolytic T lymphocytes (CTL) play an important role in the control of HIV infection. The eventual failure to contain HIV-1 infection may arise because of a functional impairment of HIV-specific CTL. We evaluated Gag-specific cytotoxicity in HIV-1-positive Ugandans. Expression of CD107, a marker for cytolytic activity, was present in CD45RA(bright) and CD45RA(dim) CD8(+) T cell populations in HIV-infected individuals. The frequency of Gag-specific CD107(+)CD45RA(bright)CD28(-)CCR7(-) CD8(+) T cells decreased with CD4 cell depletion and correlated with the presence of Gag-specific T helper response. In contrast, the frequency of Gag-specific CD107(+)CD45RA(dim)CD28(-)CCR7(-) CD8(+) T cells within the same individuals has no significant association with viral load or CD4 cell count. The ratio of CD45RA(bright) to CD45RA(dim) CTL correlates significantly with CD4 cell count. This positive association decreases with antiretroviral treatment (ARV), indicating that suppression of viral replication alters the balance of circulating Gag-specific CD8(+) effector T cells. Subsets of cytolytic T cells may have distinct antiviral functions and further characterization of these effector CD8(+) T cells may yield important information on T cell regulation and dysfunction in HIV infection.

Changes in T-cell subpopulations during four years of suppression of HIV-1 replication in patients with advanced disease

We compared the number/percentages of naive and memory CD4+ T-cells, CD38+ CD8+ T-cells, and CD28+ CD4+ and CD28+ CD8+ T-cells in patients with advanced HIV disease (baseline CD4+ count < 100) with those with less advanced (baseline CD4+ cell count > 100) HIV disease during 4 years of suppressive highly active antiretroviral therapy. This prospective, longitudinal study included 30 treatment-naive patients and 32 controls. Advanced HIV-infected patients (n = 13) gained more CD4+ T-cells than less advanced patients (n = 11) at 1 month (median: 60 vs. 36 microL(-1)), 3 months (86 vs. 14), 6 months (111 vs. 23), 12 months (174 vs. 47), 24 months (162 vs. 72) and 48 months (257 vs. 123) (P = 0.15, P < 0.001, P = 0.026, P = 0.021, P = 0.1 and P = 0.06, respectively). Advanced patients gained more naive CD4+ T-cells at 48 months compared to less advanced patients (27.3 vs. 11.4%, P = 0.05). The relative gain in memory CD4+ T-cells was greater in advanced vs. less advanced patients at 1 month (median: 6.4 vs. 1.4%), 3 months (4.3 vs. 2.0), 6 months (6.7 vs. 1.6), 12 months (6.9 vs. 2.4), 24 months (7.5 vs. 3.1) and 48 months (11.3 vs. 6.8) (P = 0.002, P = 0.013, P < 0.001, P = 0.004, P = 0.001 and P = 0.015, respectively). At 48 months, CD38+ CD8+ T-cells and naive CD4+ T-cells reached normal values (9.2%, P = 0.869 vs. controls and 47.5%, P = 0.699, respectively) in less advanced patients, as did CD38+ CD8+ T-cells in advanced patients (4.7%, P = 0.309 vs. controls). The kinetics of naive and memory CD4+ T-cell reconstitution is different in less advanced compared to advanced HIV patients.

Comparative potency of three antiretroviral therapy regimes in primary HIV infection

BACKGROUND

Virally mediated destruction of HIV-specific CD4+ T-cells in primary HIV infection (PHI) may be abrogated by potent antiretroviral therapy (ART) started in acute infection. To best achieve the most rapid reduction in primary viraemia we compared three different ART regimens in PHI.

STUDY DESIGN AND METHODS

A sequential, unblinded, non-randomized prospective cohort study. The primary endpoint was time to achieve plasma viral load (pVL) < 50 copies HIV RNA/ml. One hundred and five patients identified with PHI according to the definition: HIV antibody negative with positive HIV DNA (n = 22), HIV antibody positive with a documented negative test within the previous 6 months (n = 53), low-level incident 'detuned' assay (n = 10) or an evolving HIV-antibody test (n = 20) were recruited. Ninety of 105 individuals chose to take a short course of ART at PHI whereas 15 of 105 declined therapy. Seventy-nine of 90 were included for analysis and were allocated sequentially to either three (29 of 79) or four-drug (33 of 79) or protease inhibitor-containing ART (17 of 79).

RESULTS

A mathematical model-based analysis of viral decay indicated significantly faster viral load decline in patients receiving the four-drug regimen (P = 0.01). This conclusion was supported by a non-significant on-treatment analysis of the time taken to reach pVL <50 copies HIV RNA/ml (P = 0.07) but not by the corresponding intend-to-treat analysis. This discordance was caused by greater toxicities associated with the four-drug regimen, although the differences were not significant.

CONCLUSION

Of the three treatment regimens compared, the four-drug arm enhanced the rate of decline of primary viraemia but at the cost of toxicity.

HIV antiretroviral agents inhibit protein synthesis and decrease ribosomal protein S6 and 4EBP1 phosphorylation in C2C12 myocytes

Combined antiretroviral drug regimens have promoted clinical, immunologic, and virologic improvements in AIDS patients. Nevertheless, these therapies are associated with derangements in lipid and carbohydrate metabolism. In this study, we examined the effects of a representative protease inhibitor (nelfinavir), a nonnucleoside reverse transcriptase inhibitor (nevirapine), and a nucleoside reverse transcriptase inhibitor (zidovudine) on protein synthesis in skeletal muscle cells. To examine these processes, C2C12 myocytes were treated with increasing concentrations of nelfinavir, nevirapine, or zidovudine for 1 or 2 days, and rates of protein synthesis were determined by measuring [35S]methionine/cysteine incorporation into cellular proteins. Treatment of myocytes with therapeutic concentrations of nelfinavir, nevirapine, or zidovudine for 48 hr decreased protein synthesis by 14-20%. An approximately 60% decline was observed in cells treated with higher concentrations of nevirapine or nelfinavir. In contrast, the basal rate of protein synthesis was not affected when cells were incubated with these compounds for 24 hr. Therapeutic concentrations of nelfinavir and nevirapine did not impair the anabolic effect of insulin on protein synthesis. However, zidovudine suppressed the stimulatory effect of insulin. The decreased protein synthesis induced by nelfinavir and zidovudine was associated with decreases in the phosphorylation of the S6 ribosomal protein (rpS6) and the repressor binding protein 4EBP1, while the inhibitory effect of nevirapine was mainly associated with a decline in phosphorylated 4EBP1. In conclusion, nelfinavir, nevirapine, and zidovudine treatments decreased protein synthesis in myocytes and this effect was correlated with a reduction in the phosphorylation level of proteins that regulate translation initiation.

How effectively does HAART restore immune responses to Mycobacterium tuberculosis? Implications for tuberculosis control

Use of highly active antiretroviral treatment (HAART) has had a major impact on HIV-associated morbidity and mortality in industrialized countries. Access to HAART is now expanding in low-income countries where tuberculosis (TB) is the most important opportunistic disease. The incidence of TB has been fueled by the HIV epidemic and in many countries with high HIV prevalence current TB control measures are failing. HAART reduces the incidence of TB in treated cohorts by approximately 80% and therefore potentially has an important role in TB control in such countries. However, despite the huge beneficial effect of HAART, rates of TB among treated patients nevertheless remain persistently higher than among HIV-negative individuals. This observation raises the important question as to whether immune responses to Mycobacterium tuberculosis (MTB) are completely or only partially restored during HAART. Current data suggest that full restoration of circulating CD4 cell numbers occurs only among a minority of patients and that, even among these, phenotypic abnormalities and functional defects in lymphocyte subsets often persist. Suboptimal restoration of MTB-specific immune responses may greatly reduce the extent to which HAART is able to contribute to TB control at the community level because patients receiving HAART live much longer and yet would maintain a chronically heightened risk of TB.

Phenotypic heterogeneity of antigen-specific CD4 T cells under different conditions of antigen persistence and antigen load

The factors responsible for the phenotypic heterogeneity of memory CD4 T cells are unclear. In the present study, we have identified a third population of memory CD4 T cells characterized as CD45RA⁺CCR7^– that, based on its replication history and the homeostatic proliferative capacity, was at an advanced stage of differentiation. Three different phenotypic patterns of memory CD4 T cell responses were delineated under different conditions of antigen (Ag) persistence and load using CD45RA and CCR7 as markers of memory T cells. Mono‐phenotypic CD45RA^–CCR7⁺ or CD45RA^–CCR7^– CD4 T cell responses were associated with conditions of Ag clearance (tetanus toxoid‐specific CD4 T cell response) or Ag persistence and high load (chronic HIV‐1 and primary CMV infections), respectively. Multi‐phenotypic CD45RA^–CCR7⁺, CD45RA^–CCR7^– and CD45RA⁺CCR7^– CD4 T cell responses were associated with protracted Ag exposure and low load (chronic CMV, EBV and HSV infections and HIV‐1 infection in long‐term nonprogressors). The mono‐phenotypic CD45RA^–CCR7⁺ response was typical of central memory (T_CM) IL‐2‐secreting CD4 T cells, the mono‐phenotypic CD45RA^–CCR7^– response of effector memory (T_EM) IFN‐γ‐secreting CD4 T cells and the multi‐phenotypic response of both IL‐2‐ and IFN‐γ‐secreting cells. The present results indicate that the heterogeneity of different Ag‐specific CD4 T cell responses is regulated by Ag exposure and Ag load.

Memory responses in human immunodeficiency virus type 1-infected individuals with long-term viral load suppression are independent of CD4 cell nadir

The persistence of memory responses in suppressive highly active antiretroviral therapy (HAART) has been an area of controversy. By using a previously described proliferation assay that augments specific responses, peripheral blood lymphocytes (PBL) from 61 human immunodeficiency virus type 1-seropositive individuals with CD4 counts of >300/mm3 and suppressed viral burdens were studied for response to p24 antigen as a function of time of viral load suppression on HAART. In the majority of cases, proliferative responses could be measured in PBL from patients with plasma viral load suppression. No differences could be found in proliferative responses from PBL between individuals with a low and those with a high CD4 cell nadir. PBL that did not respond to either Casta antigen or p24 were found to have a higher percentage of naive cells than did PBL that responded well to antigen. These data support the contention that, after long-term viral load suppression, PBL from infected individuals have memory cell populations that can respond to antigenic stimulation under inducible conditions.

The case for earlier treatment of HIV infection

Current US guidelines advise that antiretroviral therapy for asymptomatic HIV patients should definitely be started for those who have CD4(+) cell counts of >200 cells/ microL, but antiretroviral therapy is often not started at CD4(+) cell counts much above that level. Guidelines advocating later therapy for HIV infection have been based mainly on sparse and limited cross-sectional data and have been predicated on avoiding drug-related toxicity and viral drug resistance. However, emerging data about factors that contribute to survival and the availability of newer, less toxic drugs are eroding this position. Earlier initiation of antiretroviral therapy--namely, for patients with CD4(+) cell counts of >350 cells/ microL--may, in fact, be associated with lower mortality, better immune improvement, and less drug-related toxicity. These findings coincide with the introduction of antiretroviral drugs that have become more effective and less difficult to take. Earlier initiation of therapy may also reduce HIV transmission, an important public health consideration, and may be beneficial in terms of overall therapeutic cost-effectiveness. Given these accumulating data, we believe reconsideration of the "when-to-start" question is timely and justified.

Attenuated poxviruses expressing a synthetic HIV protein stimulate HLA-A2-restricted cytotoxic T-cell responses

Efficient HIV vaccines have to trigger cell-mediated immunity directed against various viral antigens. However little is known about the breadth of the response induced by vaccines carrying multiple proteins. Here, we report on the immunogenicity of a construct harbouring a fusion of the HIV-1 IIIB gag, pol and nef genes (gpn) designed for optimal safety and equimolar expression of the HIV proteins. The attenuated poxviruses, MVA and NYVAC, harbouring the gpn construct, induced potent immune responses in conventional mice characterised by stimulation of Gpn-specific IFN-gamma-producing cells and cytotoxic T cells. In HLA-A2 transgenic mice, recombinant MVA elicited cytotoxic responses against epitopes recognised in most HLA-A2+ HIV-1-infected individuals. We also found that the MVA vaccine triggered the in vitro expansion of peripheral blood cells isolated from a HIV-1-seropositive patient and with similar specificity as found in immunised HLA-A2 transgenic mice. In conclusion, the synthetic HIV polyantigen Gpn delivered by MVA is immunogenic, efficiently processed and presented by human MHC class I molecules.

Detection of HIV-1 antiretroviral resistance from patients with persistently low but detectable viraemia

We modified the Abbott diagnostics HIV-1 Viroseq version 2 assay trade mark in order to detect the presence of HIV-1 drug resistance mutations in patients with viraemia below 1000 copies/ml of plasma. One hundred and forty-four patients with a detectable HIV-1 plasma viral load below 1000 copies/ml were selected and HIV-1 genetic analysis carried out using a modification of the Abbott Diagnostics Viroseq 2.0 assay trade mark. The procedure differs from the standard protocol in that a nested PCR amplification step was introduced. The oligonucleotide primers for the first round of PCR were those supplied in the RT-PCR module of the kit. The nested PCR primers were primers A and H taken from the sequencing module. One hundred and twenty-eight out of 144 (89%) plasma samples with an HIV-1 viral load of less than 1000 copies/ml (ranging from 54 to 992 copies) were successfully sequenced. HIV-1 genotypes were obtained from 68 out of 81 (84%) samples with a viral load of greater than 50 but less than 300 copies/ml and 60/63 (95%) of samples with a viral load of greater than 300 but less than 1000 copies/ml. Serial dilution of a sample with a high viral load did not affect the detection of resistance mutations. Multiple sequencing of samples with low viral load did not result in detection of additional mutations, although, in one sample the K103N mutation was detected in 3/6 replicates while wild-type was detected in 2/6 and a mixture of wild-type/mutant in 1/6. Samples from patients infected with both clade B and non-B clades of HIV-1 could be genotyped at low copy number. Modification of the Abbott Viroseq assay allows reproducible sequencing of the HIV-1 genome from patients with low, but detectable, plasma virus burden.

Evaluation of the impact of highly active antiretroviral therapy on immune recovery in antiretroviral naive patients

OBJECTIVES

To examine the extent of immune reconstitution in treatment-naive patients with CD4 T-cell counts <500 cells/microL following 48 weeks of highly active antiretroviral therapy (HAART).

METHODS

Thirteen antiretroviral naive patients were evaluated longitudinally for 48 weeks on HAART utilizing immune functional and lymphocyte phenotyping assays, including lymphocyte proliferation assay, flow cytometric evaluation of cell surface markers, and delayed type hypersensitivity skin tests. Virologic responses were monitored using commercially available viral load assays and gag/pol mRNA quantification using simultaneous immunophenotyping/UltraSensitive fluorescence in situ hybridization (ViroTect In Cell HIV-1 Detection Kit; Invirion, Frankfort, MI). Thymic function was evaluated for a subset of four patients using real-time polymerase chain reaction (PCR) for T-cell receptor excision circle (TREC) quantification and thymic scans using computerized axial tomography (CT) of the thymus.

RESULTS

HAART initiation resulted in a significant decline in plasma viremia and percentage of infected peripheral blood cells, and a rise in CD4 T cells from a baseline median of 207 cells/microL to a week-48 median of 617 cells/microL. The rise was predominately in CD4 memory cells. Naive T cells also increased in number, but at a slower rate. Activated (HLA-DR CD38) CD4 and CD8 T cells were elevated at baseline (24 and 62%, respectively) and declined by week 48 (17 and 36%, respectively) but did not reach normal levels. The number of Fas CD4 T cells increased from a baseline median of 169 to 381 cells/microL at week 48. Both soluble interleukin (IL)-2 and tumour necrosis factor (TNF) II receptors declined by week 48. HIV p24 lymphocyte proliferation assay responses were transiently detected in three patients. TREC values increased from a median 6400 copies/microg at baseline to a week-48 median value of 26 697 copies/microg.

CONCLUSION

Immune functional reconstitution was not achieved in these HAART naive patients.

Chemokine mRNA levels in mononucleated cells of HIV-infected patients before and after initiation of PI- versus NNRTI-containing HAART

To compare CC chemokine mRNA levels from native peripheral blood mononucleated cells (PBMCs) before and 6 months after the initiation of two different regimens of highly active antiretroviral therapy (HAART), we treated group 1 (n = 11) with two nucleoside analogues and the protease inhibitor (PI) indinavir boosted by ritonavir (800/100 mg b.i.d.); group 2 (n = 8) was treated with the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz instead of PI. CC chemokine mRNA levels (regulated upon T cell activation expressed secreted [RANTES], macrophage inhibitory protein [MIP]-1alpha, MIP-1beta, monocyte chemotactic protein [MCP]-1, MCP-2) were quantified from PBMCs before and 6 months after the initiation of HAART using a reverse transcription/real-time polymerase chain reaction (PCR) assay. The mRNA levels of MCP-1 and MCP-2 were significantly decreased in both groups (P < 0.05), while MIP-1alpha and MIP-1beta were decreased significantly only in the PI-treated group, but not in the NNRTI group. A moderate decrease of RANTES was observed in both treatment groups. The data suggest that HAART regimens containing either NNRTI or PI are not equivalent with regard to modification of CC chemokine mRNA profiles.

Skewed representation of functionally distinct populations of virus-specific CD4 T cells in HIV-1-infected subjects with progressive disease: changes after antiretroviral therapy

HIV-1- and cytomegalovirus (CMV)-specific CD4 T-cell-mediated antiviral immunity was evaluated by assessing the frequency of interleukin 2 (IL-2)- and interferon gamma (IFN-gamma)-secreting cells following antigen-specific stimulation in blood and lymph node. HIV-1-infected subjects with progressive disease at early stage of infection with no previous history of antiretroviral therapy (ART), subjects with nonprogressive disease, and HIV-negative subjects were studied. On the basis of the ability to secrete IL-2 and IFN-gamma, 3 functionally distinct populations of CD4 T cells were identified: (1) IL-2-secreting cells; (2) IL-2/IFN-gamma-secreting cells; and (3) IFN-gamma-secreting cells. CMV-specific CD4 T cells were almost equally distributed within the 3 functionally distinct cell populations in the 3 study groups as well as HIV-1-specific CD4 T cells in subjects with nonprogressive disease. However, a skewing toward IFN-gamma-secreting cells (70% of HIV-1-specific CD4 T cells) was observed in subjects with progressive disease, and IL-2- and IL-2/IFN-gamma-secreting cells were almost absent. The frequencies of IL-2- and of IL-2/IFN-gamma-secreting HIV-1-specific CD4 T cells were negatively correlated with the levels of viremia. Interestingly, prolonged ART was able to correct the skewed representation of different populations of HIV-1-specific CD4 T cells but was associated with only a partial recovery of IL-2-secreting cells. These results indicate that the composition of the pool of functionally distinct virus-specific CD4 T cells is important for virus control.

Determinants of long-term highly active antiretroviral treatment efficacy

OBJECTIVES

Predictors of the efficacy of highly active antiretroviral therapy (HAART) have been investigated in several studies. To increase current knowledge, the study aimed to acquire comprehensive data over an extended observation time, to obtain information on possible performance differences among individual drugs, and to identify factors with influence on the initial response to a HAART regimen and the sustainability of the response.

METHODS

The data were obtained from a prospective, single University Medical School HIV cohort. Clinical, laboratory, and treatment parameters for 475 patients were collected over 4.5 years. HAART efficacy was determined by analysis of variance and multivariate survival analysis.

RESULTS

The overall initial complete response (CR) (<500 HIV-1 RNA copies/mL) was 76.3%. Use of indinavir [odds ratio (OR)=2.747, P=0.0009] and the number of new nucleoside reverse transcriptase inhibitors (NRTIs) (OR=1.862, P=0.0017) were positively associated with CR, while initial peripheral blood HIV RNA concentration (OR=0.383, P<0.0001), use of saquinavir hard gel capsules (OR=0.531, P=0.0302), the number of successive HAART regimens (OR=0.631, P<0.0001), and the number of previously used NRTIs (OR=0.728, P=0.0081) were negatively associated with CR. Sustainability of CR was positively correlated with use of indinavir [hazard ratio of relapse (HR)=0.255, P<0.0001] and haemoglobin levels (HR=0.873, P=0.0124), but negatively correlated with initial HIV RNA concentration (HR=1.273, P=0.0003) and the number of previously used NRTIs (HR=1.587, P<0.0001). A higher number of consecutive HAART regimens was associated with a markedly reduced CR, but with only a slightly higher risk of relapse.

CONCLUSIONS

The initial response to HAART, as well as long-term efficacy, depends strongly on a few fundamental parameters that can easily be assessed in a clinical setting. There is a need for effective suppression of HIV replication over decades, and these factors should be considered early in treatment planning to identify patients with an unfavourable profile of risk factors for treatment failure.

Antigen-presenting cell modulation induces a memory response to p24 in peripheral blood leukocytes from human immunodeficiency virus-infected individuals

The accurate determination of human immunodeficiency virus type 1 (HIV-1)-specific proliferative responses is critically important when evaluating immune recovery after highly active antiretroviral therapy. Using a new assay to enhance proliferative responses to recall and HIV antigen, we addressed the questions of whether viral load affects cellular immunity and whether long-term viral load suppression results in loss of antigen-specific responder cells. This assay is based on the fact that lipopolysaccharide (LPS) can augment proliferative responses to antigen after monocyte adherence to a tissue culture plate. Twenty-six HIV-1-infected individuals donated peripheral blood leukocytes (PBL). Proliferation assays against p24, using LPS and cell adherence, were performed on all samples. Medical record abstraction provided information on CD4 cell nadir and time of viral load suppression. PBL from HIV-1-infected individuals with a viral load of <200 copies/ml had a significant proliferative response and a stimulation index of >5 to p24 (12 of 15) compared to those with a viral burden (2 of 11), using the LPS-adherence assay. Proliferative responses to p24 could be found in PBL from virally suppressed donors independent of the CD4 cell nadirs and in the majority of the donors who were virally suppressed for >10 months (7 of 10). The data presented here demonstrate that LPS and monocyte adherence provide a sensitive and specific way to boost proliferative responses to recall and HIV antigens.

The potential for CD4 cell increases in HIV-positive individuals who control viraemia with highly active antiretroviral therapy

OBJECTIVES

To study the long-term CD4 cell responses to highly active antiretroviral therapy (HAART) in treatment-naive patients whose viral loads remained below 500 copies/ml for prolonged periods.

DESIGN

A total of 237 patients whose viral loads remained below 500 copies/ml for one year or more. Median follow-up was 1.9 years.

METHODS

CD4 cell counts were analysed to investigate long-term immunological response using mixed-effects models with the slope allowed to change after 1, 12 and 24 months of HAART.

RESULTS

The median baseline CD4 cell count was 175 cells/mm3. After an initial rapid increase in the first month after HAART (97.2 cells/mm3 a month), increases in CD4 cell counts continued less rapidly (11.6 cells/mm3 a month). This increase slowed by 2.4 cells/mm3 a month after one year. CD4 cell counts continued increasing after 2 years, but the rate of increase again slowed (estimated slope at 2 years 5.4 cells/mm3 a month; decrease in slope from year 2 compared with years 1-2 3.7 cell/mm3 a month). A total of 198 out of 211 patients (94%) with measurements at baseline and one year experienced an increase in CD4 cell counts in this interval; 81 and 67% had an increasing slope between 1 and 2 and 2 and 3 years, respectively. By the end of follow-up, CD4 cell counts had increased by 319 cells/mm3, and were more than 500 cells/mm3 in 40% of patients.

CONCLUSION

Although the rate of immune recovery slowed after 2 years, CD4 cell counts rose in most and began to return to levels seen in HIV-negative individuals.

Drug Resistance Genotypes Predict Response to Amprenavir-Containing Regimens in Highly Drug-Experienced HIV-1-Infected Patients

We have undertaken a study of virological responses to amprenavir-containing antiretroviral regimens, during the expanded access programme within the UK. Ninety-five HIV-1-infected patients were included for which virological and immunological follow-up was available for 75, and baseline drug resistance data available for 51. These were highly drug-experienced patients, having previously received a median of nine antiviral drugs, within all available classes. Eighty-eight percent of patients had a virological response to the new regimen, with a median maximal decline of 1.45 log10 copies/ml, and 34% of patients reached <400 copies/ml on treatment. Although 68% of patients with resistance data had protease inhibitor resistance mutations, only 10% patients had key amprenavir resistance mutations, and virological response was predicted by the number of active drugs utilized in the amprenavir-containing regimen, as determined by the baseline genotypic resistance test. Other independent predictors of viral load decline were a higher baseline viral load and fewer previous antiviral drugs. We conclude that amprenavir can contribute to antiviral efficacy in salvage regimens, and that resistance testing may help to optimize its use in this scenario. New formulations of amprenavir, together with boosted regimens, may enhance the activity in the presence of protease inhibitor-resistant virus.

Factors associated with the evolution of the viral load in individuals with HIV infection

The temporal evolution of the viral load (VL) in a group of patients under clinical care and the identification of individual variables that determined this evolution was studied using a retrospective descriptive study of the VL determinations on 1336 patients between September 1996 and June 2000. During follow-up, patients' VLs increasingly fell below the detection threshold. Those patients who had received antiretroviral treatment prior to the monitoring of the viraemia presented lower VLs at the start of their follow-up. Those patients who had been cared for on the same unit throughout their follow-up maintained lower VLs. Female patients uniformly presented lower VL results than the males. The immunological status at the beginning of follow-up and the basal VL determined the initial evolution of the patients' VL, although it did not do so in the final stages of follow-up. The immunological and virological state at the onset of the follow-up determines the evolution of the patients' VL.

Distribution and functional analysis of memory antiviral CD8 T cell responses in HIV-1 and cytomegalovirus infections

In the present study, we have investigated the anatomic distribution and the function of different populations of HIV-1- and cytomegalovirus (CMV)-specific memory CD8 T cells. The different populations of virus-specific memory CD8 T cells were distinguished on the basis of the expression of CD45RA and CCR7, and the composition of HIV-1- and CMV-specific memory CD8 T cell pools were compared in subjects with chronic HIV-1 and CMV co-infection. The distribution of HIV-1-specific CD8 T cells was similar between blood and lymph node. However, CMV-specific CD8 T cells were accumulated predominantly in the blood away from the lymphoid tissue. The majority (>70%) of HIV-1- and CMV-specific CD8 T cells in both blood and lymph node had a phenotype, e.g. CCR7-, typical of effector T cells. HIV-1-specific memory CD8 T cells were mostly (>80%) pre-terminally differentiated cells, e.g. CD45RA-CCR7-, in both blood and lymph node while 30-50% of CMV-specific CD8 T cells were terminally differentiated, e.g. CD45RA+CCR7-. Therefore, consistently with studies in mice, antigen-specific effector memory CD8 T cells accumulate predominantly in the target organ of the pathogen in humans, and the differences in the composition of HIV-1- and CMV-specific CD8 T cell pools were also present in the lymphoid tissue. A substantial proportion (30-40%) of virus-specific CD8+CCR7+ T cells produced IFN-gamma. Thus, indicating that the expression of CCR7 does not provide a clear-cut separation of memory CD8 T cells with distinct functional capacities. Taken together, these results provide further advances in the characterization of human memory CD8 T cells.

HIV disease and advanced age: an increasing therapeutic challenge

The mean age of patients at both first HIV detection and AIDS diagnosis is progressively rising over time. However, reliable epidemiological estimates, clinical data or controlled therapeutic and outcome figures are lacking for elderly patients, especially with regard to laboratory and clinical response to antiretroviral therapy, treatment tolerability, drug-drug interactions, short- and long-term toxicity, and interactions with underlying illnesses and concurrent pharmacological treatment. In fact, the large majority of randomised, controlled trials evaluating and comparing new antiretroviral drugs or anti-HIV therapeutic strategies, as well as antimicrobial treatment or chemoprophylaxis of HIV-related complications, either excluded patients with advanced age and/or concurrent disorders or did not offer substudies or detailed data analysis focusing on older patients compared with younger ones. The life expectancy of HIV-infected persons receiving highly active antiretroviral therapy (HAART) is now extended (approaching that of the general population), so that the definition of AIDS has lost its epidemiological and clinical significance thanks to the immune reconstitution resulting from potent antiretroviral therapy. However, an ever-increasing number of individuals aged > or =50 years with HIV infection is expected in the coming years, as a result of both increased survival of patients with treated disease and delayed recognition of individuals with occult HIV disease. The limited data available about combined antiretroviral therapy in the elderly seem to show an overlapping virological success rate but a slower and blunted immune recovery compared with younger patients. Thymic output, however, seems somewhat preserved even in adulthood and may contribute to the reconstitution of most of the quantitative and functional T cell abnormalities caused by HIV disease. More attention must be paid to underlying end-organ disorders, as well as expected pharmacological interactions and combined drug toxicity that may interfere with HAART efficacy and patients' compliance with recommended regimens and could lead to increased adverse effects. The available guidelines for antiretroviral treatment and therapy and prophylaxis of AIDS-related illnesses should be regularly updated and should include problems related to HIV disease in an aging population. Specific trials or substudies focusing on older people are warranted to obtain controlled data on all issues of antiretroviral therapy in the elderly, including time and mode of initiation, and modification and salvage HAART regimens. Antiretroviral drug dosage adjustment to take into account underlying pathological conditions or other pharmacological treatments is another emerging issue.

Virological and immunological effects of short-course antiretroviral therapy in primary HIV infection

BACKGROUND

National and international guidelines call for the treatment of primary HIV infection (PHI) with combination antiretroviral therapy, although the ideal timing and duration of this intervention is unknown. Recent immunological studies of antiretroviral therapy on small numbers of patients with PHI have reported preservation of HIV-specific CD4 T-helper responses, ordinarily lost in the absence of intervention. We sought to investigate whether a short course of antiretroviral therapy (SCART) at PHI was sufficient to preserve HIV-specific cellular immunity.

METHODS

Forty-five subjects with confirmed PHI were offered SCART at diagnosis. HIV specific cellular immune responses and virological parameters were assessed at monthly intervals.

RESULTS

Thirty-seven of the subjects chose SCART at PHI, and achieved a plasma viral load < 50 RNA copies/ml by a median of 10 weeks (range, 4-32 weeks). Two of the 45 individuals had evidence of genotypic HIV drug resistance at baseline, and none developed new mutations following therapy. All patients who received SCART at PHI showed preservation of HIV-specific CD4 T-helper responses up to 64 weeks off SCART.

CONCLUSION

SCART at PHI was safe, did not induce the development of drug resistance, and appeared sufficient to preserve HIV-specific CD4 T-helper responses. However, PHI is highly heterogeneous, and a large-scale randomized trial of SCART at PHI is now needed.

Limited immune restoration after 3 years' suppression of HIV-1 replication in patients with moderately advanced disease

OBJECTIVE

To describe the magnitude of immune restoration after long-term control of HIV-1 replication. DESIGN Prospective study of immune restoration in patients starting highly active antiretroviral therapy (HAART).

METHODS

Patients with moderately advanced HIV-1 infection (CD4 cells between 100 x 10 and 300 x 10 /l) who enrolled in a trial of HAART and who had suppression of HIV-1 replication during 3 years of therapy were evaluated for phenotypic and functional indices of immune restoration.

RESULTS

Almost all immune restoration achieved occurred during the first year. The median CD4 lymphocyte count increased by 159 x 10 cells/l during the first year (P < 0.001); CD4 lymphocyte rises during the second and third years were not significant. Most decreases in activation antigen expression (CD38/HLA-DR) on CD4 and CD8 lymphocytes occurred during the first year, and after 3 years, patient lymphocytes were still abnormally activated. The proportion of CD4 lymphocytes expressing CD28 increased during the first and second years, but even after 3 years, CD28 expression on CD4 cells remained abnormally low. Lymphocyte proliferative responses to normalized during the first 12 weeks of HAART while responses to tetanus increased only after immunization and enhanced responses to HIV-1 p24 antigen were not observed.

CONCLUSIONS

Immune restoration was incomplete in patients who started HAART with moderately advanced HIV-1 disease and most changes occurred during the first year. These data suggest that this degree of suppression of HIV-1 replication alone will not suffice to restore immune competence. The clinical significance of incomplete reconstitution of CD4 lymphocyte number, phenotype, and proliferative function in HIV-1 infection remains to be determined.

Analysis of HIV-1- and CMV-specific memory CD4 T-cell responses during primary and chronic infection

CD4 T-cell-specific memory antiviral responses to human immunodeficiency virus type 1 (HIV-1) and cytomegalovirus (CMV) were investigated in 16 patients with documented primary HIV-1 infection (4 of the 16 subjects also had primary CMV infection) and compared with those observed in patients with chronic HIV-1 and CMV coinfection. Virus-specific memory CD4 T cells were characterized on the basis of the expression of the chemokine receptor CCR7. HIV-1- and CMV-specific interferon-gamma-secreting CD4 T cells were detected in patients with primary and chronic HIV-1 and CMV coinfection and were mostly contained in the cell population lacking expression of CCR7. The magnitude of the primary CMV-specific CD4 T-cell response was significantly greater than that of chronic CMV infection, whereas there were no differences between primary and chronic HIV-1-specific CD4 T-cell responses. A substantial proportion of CD4(+)CCR7(-) T cells were infected with HIV-1. These results advance the characterization of antiviral memory CD4 T-cell response and the delineation of the potential mechanisms that likely prevent the generation of a robust CD4 T-cell immune response during primary infection.

Clinical efficacy of early initiation of HAART in patients with asymptomatic HIV infection and CD4 cell count > 350 x 10(6) /l

OBJECTIVE

To evaluate the efficacy of early initiation of highly active antiretroviral therapy (HAART), we compared the clinical course of two nested, matched cohorts within the Swiss HIV Cohort Study.

METHODS

We selected all asymptomatic patients who started HAART between 1 January 1996 and 31 December 1999 with a CD4 cell count > 350 x 10(6)/l. We then matched them with asymptomatic participants who were seen at around the same time and who remained untreated during the following 12 months. This control group was further matched for age, sex, CD4 cell count, viral load, and HIV risk category, generating 283 pairs of treated versus untreated patients.

RESULTS

During observation of median 3.19 versus 2.66 years, CDC stage B/C occurred in 6.4% versus 21.2%, AIDS in 1.8% versus 5.3%, death in 2.1% versus 6.4%, and AIDS or death of 'natural' causes in 2.8% versus 6.7% of the treated versus untreated patients. In multivariable Cox regression analysis, treatment reduced the risk of clinical progression by a factor of four- to five fold. During follow-up, the treated group had significantly higher CD4 counts and lower HIV-1 RNA levels. Intolerance/adverse events led to change or stop of at least one drug in 35% of treated patients. The entire regimen was interrupted at least once by 41% of patients, and 24% had no treatment anymore at the end of follow-up.

CONCLUSIONS

The initiation of HAART in asymptomatic patients with CD4 cell count > 350 x 10(6)/l significantly delayed clinical progression. However, the risk of severe clinical events with deferred therapy was low and must be counter balanced against the burden and toxicity of HAART.

Comparative response of African HIV-1-infected individuals to highly active antiretroviral therapy

OBJECTIVE

Few data exist on the virological response to antiretroviral therapy of individuals infected with African HIV-1 subtypes. Our objective was to compare the response, in our clinic, of African HIV-1-infected patients with their British and European contemporaries treated with the same regimes.

DESIGN

The St Mary's Hospital HIV database was used to identify drug-naive African and European patients starting a highly active antiretroviral therapy (HAART) regimen.

METHODS

HIV-1 subtype was determined by phylogenetic analysis of pol sequences. Kaplan-Meier survival analysis was used to estimate the proportion of patients achieving undetectable viral loads (< 500 copies/ml). The longer-term response to therapy was assessed by changes in CD4 cell counts and viral loads from baseline.

RESULTS

A total of 265 patients were classified as 'European' and 97 as 'African', confirmed by sequence. The time to first undetectable viral load was similar for the two groups (P = 0.9). Although there were no statistically significant differences in the CD4 cell count responses (P = 0.11), there was evidence of an increase in viral load after 9 months for the African group, resulting in a widening viral load gap between the two cohorts; the effect of ethnic group was statistically significant (P < 0.001).

CONCLUSION

The initial virological and immunological responses of the African and European cohorts to HAART were similar; although the longer-term virological response was poorer in the African cohort, which may be related to adherence. On the basis of these findings, there is no justification for withholding HAART from Africa on virological grounds.

Health care industries' perspective of viral load assays: the VERSANT HIV-1 RNA 3.0 assay

This article will compare the VERSANT HIV-1 RNA 3.0 (bDNA 3.0) assay with other HIV-1 viral load assays, particularly the AMPLICOR HIV-1 MONITOR (Amplicor 1.5), the industry standard. The discussion will cover the history of viral load assay development and challenges to the field. It will finish with a description of the evolving markets for viral load assays in the developing world and the impact of variations in the different assays on their ability to reach those markets and patient populations.

Results of 2 years of treatment with protease-inhibitor--containing antiretroviral therapy in dutch children infected with human immunodeficiency virus type 1

Clinical, virologic, and immunologic responses to treatment that contained either indinavir or nelfinavir (both regimens included zidovudine and lamivudine) were determined in 32 children infected with human immunodeficiency virus type 1 (HIV-1) who participated for >/= 96 weeks in a prospective, open, uncontrolled multicenter trial. The pharmacokinetics of indinavir and of nelfinavir were determined and showed large interindividual differences. After 96 weeks of therapy, 69% and 50% of the patients had an HIV-1 RNA load that was below the HIV assays' detection limits of 500 and 40 copies/mL, respectively. Virologic failure was associated with poor compliance and younger age (independent of baseline virus load and receipt of pretreatment). Relative CD4 cell counts increased significantly in relation to the median of the age-specific reference value, from a median of 44% at baseline to 94% after 96 weeks. In a high percentage of the children, clinical, virologic, and immunologic response rates to combination therapy were optimal during the initial 2 years of therapy.