An algorithm-based genotypic resistance score is associated with clinical outcome in HIV-1-infected adults on antiretroviral therapy

OBJECTIVES: The aim of this study was to evaluate the association between genotypic drug resistance and the occurrence of HIV-related diseases and death in HIV-1-infected adults on antiretroviral therapy. METHODS: We performed an observational study on patients from an out-patient clinic in a university hospital. Genotypic drug resistance analysis after virological treatment failure was performed in 141 patients receiving two or more antiretroviral drugs. All patients had follow up of at least 6 months after the resistance test. An algorithm was developed to estimate the level of genotypic drug resistance and to assign an actual resistance score (ARS) for the drugs prescribed to each patient. The patient population was divided into quartiles according to patients' ARS values. Our endpoint was the risk of developing an HIV-related disease [Centers for Disease Control and Prevention (CDC) category B or C] during the period starting 6 months prior to and ending 6 months after the genotypic resistance test, or death during the 6 months following the resistance test. RESULTS: There was a significant association between the level of resistance to the drugs prescribed (ARS) and our clinical endpoint: the odds ratio for an endpoint (with 95% confidence interval) was 3.20 (1.28-7.99), adjusted for CD4 cell count and HIV RNA, in patients in the highest ARS quartile compared with patients in the other three quartiles. CONCLUSIONS: Our study indicates that patients with high-level genotypic drug resistance are at increased risk of developing an HIV-related disease. This association could not be explained by differences in CD4 cell count or HIV RNA levels.     

The naive CD4+ count in HIV-1-infected patients at time of initiation of highly active antiretroviral therapy is strongly associated with the level of immunological recovery

Current antiretroviral therapy can induce considerable, sustained viral suppression followed by immunological recovery, in which naive CD4 + cells are important. Long-term immunological recovery was investigated during the first 3 y of highly active antiretroviral therapy (HAART) in 210 HIV-1-infected patients. The focus was on the naive CD4 + cell time course and associations between naive CD4 + cell counts and established prognostic markers. Total and naive CD4 + cell counts were measured using flow cytometry. The HIV-RNA detection limit was 20 copies/ml. During 36 months of HAART, the total CD4 + count followed a triphasic pattern, reflecting an initial phase of rapid redistribution from lymphoid tissues, followed by a slow increase, partially due to an increase in naive CD4+ cell count. From Month 18 onwards, both naive and total CD4 + cell counts stabilized, although viral suppression was sustained. There was no association between plasma viral load and the increase in naive CD4 + cell count. Importantly, baseline naive CD4 + cell count was significantly associated with the change in naive CD4 + cell count, suggesting that the naive cell count at baseline does influence the immunological recovery that can be obtained from treatment. Surprisingly, the naive CD4 + cell count tended to stabilize at a subnormal level after 18 months of HAART. This finding merits further investigation.     

Differential CD4 T-cell response in HIV-1-infected patients using protease inhibitor-based or nevirapine-based highly active antiretroviral therapy

Objectives

To study the dynamics of CD4 T‐lymphocyte counts (CD4 counts) after the initiation of either protease inhibitor (PI)‐based or nevirapine (NVP)‐based first‐line highly active antiretroviral therapy (HAART).

Design and methods

A retrospective cohort study of 1029 HIV‐infected antiretroviral therapy‐naive patients initiating either PI‐based or NVP‐based HAART was carried out. Patients were censored as soon as they experienced virological failure, or changed their original antiretroviral regimen for any reason.

Results

In total, 920 and 109 patients initiated PI‐ and NVP‐based HAART, respectively. The patients in the PI group more often had AIDS (15 vs. 6% in the NVP group), had a lower median baseline CD4 count (234 vs. 250 cells/μL in the NVP group) and had higher median baseline plasma HIV‐1 RNA levels (pVL) (5.0 vs. 4.7 log₁₀ HIV‐1 RNA copies/mL in the NVP group). After 96 weeks of follow‐up, the mean increase from baseline in CD4 count, adjusted for baseline CD4 count, age, gender and baseline pVL, was 310 cells/μL in the PI group and 212 cells/μL in the NVP group (P=0.003). This difference was mainly attributable to the patients in the NVP group initiating HAART with a baseline CD4 count below 200 cells/μL. There were no differences between the PI and NVP groups with respect to the change in the number of CD4 cells as a proportion of the total number of lymphocytes.

Conclusion

Patients successfully treated with NVP‐based HAART have a smaller increase in absolute CD4 cells compared with those treated with PI‐based HAART.

     

CD38 expression on CD8 T cells has a weak association with CD4 T-cell recovery and is a poor marker of viral replication in HIV-1-infected patients on antiretroviral therapy

OBJECTIVE: The aim of the study was to determine whether the expression of CD38 on CD8 T cells can identify patients with virological failure on antiretroviral therapy (ART). DESIGN: This was a cross-sectional study of patients attending a single HIV clinic in London. METHODS: The expression of CD38 on CD8 T cells was assessed using a biologically calibrated flow cytometry protocol. Patients were characterized by lymphocyte subset and viral load measurements. Characteristics including historical CD4 T cell counts, therapeutic history, co-infections and demographics were obtained from medical records. RESULTS: Elevated levels of CD8 CD38(high) T cells were found in HIV-1-infected patients who failed to suppress viral replication with ART; however, this parameter lacked sufficient sensitivity and specificity to replace viral load testing in assessing the efficacy of ART. Increased levels of CD8 CD38(high) cells were associated with reduced CD4 T cell counts in HIV-1-infected patients on ART after correcting for known determinants of CD4 T-cell recovery. CONCLUSIONS: The expression of CD38 on CD8 T cells lacks sufficient sensitivity and specificity to be used as a surrogate marker for viral load to monitor HIV-1 infection. T-cell activation is associated with reduced CD4 T-cell reconstitution in patients receiving ART.     

Characteristics of HIV-1-infected patients with CD4:CD8 lymphocyte ratio normalization on antiretroviral therapy

Antiretroviral therapy for human immunodeficiency virus (HIV)-infection results in normalization of CD4:CD8 T-lymphocyte ratio in about 6% of cases. The T-cell ratio normalization on therapy was associated with a baseline CD4 of over 350 cells per microliter and a T-cell ratio of over 0.5 (for each, p < 0.01), but not with the current level of viral load suppression or compliance with clinic appointments (for each, p > 0.05). The patients with T-cell ratio normalization had a baseline median CD4 count of 428 cells per microliter (range, 353-883 cells per microliter) and a median T-cell ratio of 0.75 (range, 0.54-0.87). We could not address the effect of baseline viral load on T-cell ratio normalization, but there was no association with age, gender, race, HIV risk factor, or the length of antiretroviral therapy.     

Gag-specific CD4+ T-cell responses are associated with virological control of paediatric HIV-1 infection

HIV-specific Elispot responses were investigated in 57 antiretroviral therapy-naive children, of median age 9.9 years. CD8(+) T-cell responses were detected in 96% children; Nef was the immunodominant protein. Responses broadened over time, but there was no association between magnitude, breadth or specificity of response and viraemia. Gag-specific CD4(+) T-cell responses, detectable in 26% children, correlated inversely with viraemia (R = -0.43, P < 0.001), suggesting that preservation of this cell population may be an important goal of therapeutic/vaccine strategies.     

CD4+ T-cell deficiency in HIV patients responding to antiretroviral therapy is associated with increased expression of interferon-stimulated genes in CD4+ T cells

Most patients with human immunodeficiency virus (HIV) who remain CD4(+) T-cell deficient on antiretroviral therapy (ART) exhibit marked immune activation. As CD4(+) T-cell activation may be mediated by microbial translocation or interferon-alpha (IFN-α), we examined these factors in HIV patients with good or poor CD4(+) T-cell recovery on long-term ART. Messenger RNA levels for 3 interferon-stimulated genes were increased in CD4(+) T cells of patients with poor CD4(+) T-cell recovery, whereas levels in patients with good recovery did not differ from those in healthy controls. Poor CD4(+) T-cell recovery was also associated with CD4(+) T-cell expression of markers of activation, senescence, and apoptosis, and with increased serum levels of the lipopolysaccharide receptor and soluble CD14, but these were not significantly correlated with expression of the interferon-stimulated genes. Therefore, CD4(+) T-cell recovery may be adversely affected by the effects of IFN-α, which may be amenable to therapeutic intervention.     

Sub-optimal CD4 recovery on long-term suppressive highly active antiretroviral therapy is associated with favourable outcome

Objectives To examine risk factors for sub-optimal CD4 recovery on suppressive highly active antiretroviral therapy (HAART) and assess long-term clinical and immunological outcomes.
Methods Retrospective analysis of 286 HIV-positive patients from a university clinic who initiated HAART with CD4 count <350 cells/μL between January 1996 and July 2006 and achieved ≥52 weeks of viral suppression (VS). Sub-optimal and optimal CD4 count recovery were defined by gains of <150 and ≥150 cells/μL during the first year of VS, respectively. Risk factors were analysed by multivariate logistic regression and markers of immune maturation and activation were evaluated prospectively for a sub-group of patients with prolonged (>5 years) VS.
Results One hundred and two (36%) patients had sub-optimal CD4 recovery. Male gender, lower pre-HAART viral load, HAART toxicity and use of opportunistic infection (OI) prophylaxis were independent risk factors on multivariate analysis ( P <0.05). Outcomes of duration of VS on HAART (4 years), new OI events (1%) and mortality (5%) were similar between groups. Markers of immune maturation and activation were higher among patients with sub-optimal CD4 recovery ( P <0.05).
Conclusions Among HIV-positive patients with long-term VS, sub-optimal CD4 recovery was common but morbidity and mortality remained low. In addition, persistent CD4 T-cell activation appeared to blunt long-term CD4 gains.     

Prevalence of CXCR4 tropism among antiretroviral-treated HIV-1-infected patients with detectable viremia

Although CXCR4-tropic viruses are relatively uncommon among untreated human immunodeficiency virus (HIV)-infected individuals except during advanced immunodeficiency, the prevalence of CXCR4-tropic viruses among treated patients with detectable viremia is unknown. To address this issue, viral coreceptor usage was measured with a single-cycle recombinant-virus phenotypic entry assay in treatment-naive and treated HIV-infected participants with detectable viremia sampled from 2 clinic-based cohorts. Of 182 treated participants, 75 (41%) harbored dual/mixed or X4-tropic viruses, compared with 178 (18%) of the 976 treatment-naive participants (P<.001). This difference remained significant after adjustment for CD4+ T cell count and CCR5 Delta 32 genotype. Enrichment for dual/mixed/X4-tropic viruses among treated participants was largely but incompletely explained by lower pretreatment nadir CD4 + T cell counts. CCR5 inhibitors may thus be best strategically used before salvage therapy and before significant CD4 + T cell depletion.     

Selective stimulation of CD4+ versus CD8+ T-cell subsets in symptomatic and asymptomatic HIV-1-infected individuals.

To analyze the proliferative capacity of CD4+ or CD8+ T-cell subsets of individuals infected with human immunodeficiency virus type 1 (HIV-1) and to optimize the in vitro conditions for virus replication, CD4+ or CD8+ cells of HIV-1-infected patients were selectively activated inside the whole peripheral blood mononuclear cell (PMNC) population by dual antibody stimulation. To do so PMNC of HIV-1-infected individuals were stimulated with the per se nonmitogenic anti-CD3 antibody fragment BMA030 F(ab)2 crosslinked through goat antimouse antibodies with an anti-CD4 or an anti-CD8 antibody, which lead to selective proliferation of either the CD4+ or the CD8+ T-cell subset. In the presence of monocyte supernatant and recombinant interleukin-2 (rIL2) CD4+ cells of HIV-1 patients responded normally upon such stimulation as their proliferation correlated (r = 0.9) to the percentage CD4+ cells present in the PMNC population. Selective stimulation and proliferation of CD8+ cells could, however, only partially be elicited by dual antibody stimulation, even in the presence of rIL-2 and monocyte supernatant. Their proliferative response did not correspond (r = 0.1) to the percentage CD8+ cells present in the PMNC culture. A positive correlation (r = 0.7) was detected only between percentage CD8+ HLA-DR- cells and proliferation. This confirmed previous studies showing that the defective in vitro proliferative response of peripheral blood lymphocytes of HIV-infected individuals to mitogens, which is usually interpreted being due to a CD4 cell defect, is actually due to a failure of CD8+DR+ cells to proliferate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Slow disease progression and robust therapy-mediated CD4+ T-cell recovery are associated with efficient thymopoiesis during HIV-1 infection

In chronic HIV infection, most untreated patients lose naive CD4+ and CD8+ T cells, whereas a minority preserve them despite persistent high viremia. Although antiretroviral therapy (ART)-mediated viral suppression generally results in a rise of naive and total CD4+ T cells, certain patients experience very little or no T-cell reconstitution. High peripheral T-cell activation has been linked to poor clinical outcomes, interfering with previous evaluations of thymic function in disease progression and therapy-mediated T-cell recovery. To circumvent this, we used the sj/betaTREC ratio, a robust index of thymopoiesis that is independent of peripheral T-cell proliferation, to evaluate the thymic contribution to the preservation and restoration of naive CD4+ T cells. We show that the loss of naive and total CD4+ T cells is the result of or is exacerbated by a sustained thymic defect, whereas efficient thymopoiesis supports naive and total CD4+ T-cell maintenance in slow progressor patients. In ART-treated patients, CD4+ T-cell recovery was associated with the normalization of thymopoiesis, whereas the thymic defect persisted in aviremic patients who failed to recover CD4+ T-cell counts. Overall, we demonstrate that efficient thymopoiesis is key in the natural maintenance and in therapy-mediated recovery of naive and total CD4+ T cells.     

Unrecognised tuberculosis at antiretroviral therapy initiation is associated with lower CD4+ T cell recovery

Objectives To investigate whether an unrecognised diagnosis of tuberculosis (TB) at the start of antiretroviral therapy (ART) influences subsequent CD4+ T cell (CD4) count recovery in an urban HIV clinic in Uganda. Methods In a retrospective cohort study, a multivariable polynomial mixed effects model was used to estimate CD4 recovery in the first 96 weeks of ART in two groups of patients: prevalent TB (started ART while on TB treatment), unrecognised TB (developed TB within 6 months after start ART). Results Included were 511 patients with a median baseline CD4 count of 57 cells/mm³ (interquartile range: 22–130), of whom 368 (72%) had prevalent TB and 143 (28%) had unrecognised TB. Compared with prevalent TB, unrecognised TB was associated with lower CD4 count recovery at 96 weeks: ?22.3 cells/mm³ (95% confidence interval ?43.2 to ?1.5, P = 0.036). These estimates were adjusted for gender, age, baseline CD4 count and the use of zidovudine‐based regimen. Conclusions Unrecognised TB at the time of ART initiation resulted in impaired CD4 recovery compared with TB treated before ART initiation. More vigilant screening with more sensitive and rapid TB diagnostics prior to ART initiation is needed to decrease the risk of ART‐associated TB and sub‐optimal immune reconstitution.     

Effects of viremia and CD4 recovery on gut “microbiome-immunity” axis in treatment-naïve HIV-1-infected patients undergoing antiretroviral therapy

BACKGROUNDHuman immunodeficiency virus type 1 (HIV-1) infection is characterized by persistent systemic inflammation and immune activation, even in patients receiving effective antiretroviral therapy (ART). Converging data from many cross-sectional studies suggest that gut microbiota (GM) changes can occur throughout including human immunodeficiency virus (HIV) infection, treated by ART; however, the results are contrasting. For the first time, we compared the fecal microbial composition, serum and fecal microbial metabolites, and serum cytokine profile of treatment-naïve patients before starting ART and after reaching virological suppression, after 24 wk of ART therapy. In addition, we compared the microbiota composition, microbial metabolites, and cytokine profile of patients with CD4/CD8 ratio < 1 (immunological non-responders [INRs]) and CD4/CD8 > 1 (immunological responders [IRs]), after 24 wk of ART therapy.AIMTo compare for the first time the fecal microbial composition, serum and fecal microbial metabolites, and serum cytokine profile of treatment-naïve patients before starting ART and after reaching virological suppression (HIV RNA < 50 copies/mL) after 24 wk of ART.METHODSWe enrolled 12 treatment-naïve HIV-infected patients receiving ART (mainly based on integrase inhibitors). Fecal microbiota composition was assessed through next generation sequencing. In addition, a comprehensive analysis of a blood broad-spectrum cytokine panel was performed through a multiplex approach. At the same time, serum free fatty acid (FFA) and fecal short chain fatty acid levels were obtained through gas chromatography-mass spectrometry.RESULTSWe first compared microbiota signatures, FFA levels, and cytokine profile before starting ART and after reaching virological suppression. Modest alterations were observed in microbiota composition, in particular in the viral suppression condition, we detected an increase of Ruminococcus and Succinivibrio and a decrease of Intestinibacter. Moreover, in the same condition, we also observed augmented levels of serum propionic and butyric acids. Contemporarily, a reduction of serum IP-10 and an increase of IL-8 levels were detected in the viral suppression condition. In addition, the same components were compared between IRs and INRs. Concerning the microflora population, we detected a reduction of Faecalibacterium and an increase of Alistipes in INRs. Simultaneously, fecal isobutyric, isovaleric, and 2-methylbutyric acids were also increased in INRs. CONCLUSIONOur results provided an additional perspective about the impact of HIV infection, ART, and immune recovery on the “microbiome-immunity axis” at the metabolism level. These factors can act as indicators of the active processes occurring in the gastrointestinal tract. Individuals with HIV-1 infection, before ART and after reaching virological suppression with 24 wk of ART, displayed a microbiota with unchanged overall bacterial diversity; moreover, their systemic inflammatory status seems not to be completely restored. In addition, we confirmed the role of the GM metabolites in immune reconstitution.     

Serum HIV-1 RNA load to predict CD4+ T-cell depletion in asymptomatic patients

Summary The temporal association between the increase in viral replication and the depletion in CD4⁺ T cells in HIV-1 infection is not yet clear. To investigate this phenomenon HIV-1 RNA was quantified in several frozen sera from 20 asymptomatic HIV-1 infected patients in the 2 years preceding CD4⁺ T cell depletion of 50% or more, and compared with 20 HIV-1 infected paired patients who were stable in the same period. In each group, no statistically significant variation in the mean HIV-1 RNA titre was found between the last checkup and the one 24 months earlier. The mean HIV-1 RNA titre was 10^3.86 copies/ml in the non-progressor group and 10^5.12 copies/ml in the progressor group. These data support the view that the quantity of circulating HIV-1 RNA is an early predictor of disease progression that is relatively constant during the asymptomatic period of HIV-1 infection.

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Vorhersagewert der Serum-HIV-1 RNA-Last für die CD4⁺-T-Zell-Depletion bei asymptomatischen Patienten

Zusammenfassung Die zeitliche Beziehung zwischen der zunehmenden Virusreplikation und Depletion der CD4⁺ T-Zellen bei HIV-1 Infektion ist noch nicht geklärt. Um dieses Phänomen zu untersuchen, haben wir eine Quantifizierung der HIV-1 RNA in mehreren Seren von 20 asymptomatischen HIV-1 infizierten Patienten durchgeführt, die in den Jahren vor einer Verminderung der CD4⁺ T-Zellen um 50% und mehr eingefroren worden waren. Die Werte wurden mit denjenigen von 20 HIV-1 infizierten Patientenpaaren verglichen, die während desselben Zeitraums stabil geblieben waren. In keiner der Gruppen fanden sich statistisch signifikante Unterschiede im mittleren HIV-1 RNA-Titer zwischen der Untersuchung zum Zeitpunkt 24 Monate und der ersten Untersuchung. In der nicht progredienten Gruppe fand sich ein mittlerer HIV-1 RNA-Titer von 10^3,86/ml Kopien, in der progredienten Gruppe 10^5,12/ml. Diese Ergebnisse sprechen dafür, daß die Menge an zirkulierender HIV-1 RNA ein früher Prädiktor der Krankheitsprogression ist, der während der asymptomatischen Phase der HIV-1 Infektion relativ konstant bleibt.

     

Microbial translocation is associated with sustained failure in CD4+ T-cell reconstitution in HIV-infected patients on long-term highly active antiretroviral therapy

Patients with inefficient CD4+ T-cell recovery on virogically suppressive highly active antiretroviral therapy constitute a major clinical hurdle given the threat of HIV/AIDS disease progression. We show heightened circulating lipopolysaccharide associated with plasma enterobacterial DNA and highly activated Ki67+CD4+CD8+ in 24 immunologic-nonresponders (CD4+ T-cell < or = 200; HIV-RNA < or = 50) compared with 11 full responders (CD4+ T-cell > or= 400; HIV-RNA < or = 50). These data provide novel insight into INRs pathogenesis, since they correlate augmented systemic translocation of microbial bioproducts with T-cell hyperactivation.