Impact of genotypic drug resistance mutations on clinical and immunological outcomes in HIV-infected adults on HAART in West Africa

OBJECTIVES: To analyse the association between the presence of resistance mutations and treatment outcomes. The impact of HIV-1 drug resistance mutations in African adults on HAART has so far never been reported. METHODS: In 2004 in Abidjan, C?te d'Ivoire, 106 adults on HAART had plasma viral load measurements. Patients with detectable viral loads had resistance genotypic tests. Patients were followed until 2006. Main outcomes were serious morbidity and immunological failure (CD4 cell count < 200 cells/microl). RESULTS: At study entry, the median previous time on HAART was 37 months and the median CD4 cell count was 266 cells/microl; 58% of patients had undetectable viral loads, 20% had detectable viral loads with no major resistance mutations, and 22% had detectable viral loads with one or more major mutations. The median change in CD4 cell count between study entry and study termination was +129 cells/microl in patients with undetectable viral loads, +51 cells/microl in those with detectable viral loads with no mutations and +3 cells/microl in those with detectable viral loads with resistance mutations. Compared with patients with undetectable viral loads, those with detectable viral loads with resistance mutations had adjusted hazard ratios of immunological failure of 4.32 (95%CI 1.38-13.57, P = 0.01). One patient died. The 18-month probability of remaining free of morbidity was 0.79 in patients with undetectable viral loads and 0.69 in those with resistance mutations (P = 0.19). CONCLUSION: In this setting with restricted access to second-line HAART, patients with major resistance mutations had higher rates of immunological failure, but most maintained stable CD4 cell counts and stayed alive for at least 20 months.     

Change in transaminases in hepatitis C virus- and HIV-coinfected patients after highly active antiretroviral therapy: differences between complete and partial virologic responders?

Patients with HIV and hepatitis C virus (HCV) coinfection have more severe hepatitis-related disease than do patients with HCV infection alone. Highly active antiretroviral therapy (HAART) with protease inhibitor appears to restore pathogen-specific immune responses, especially in patients with persistent undetectable HIV viral load. To evaluate the potent impact of immune restoration induced by HAART on the course of HCV-related disease, HCV viremia and levels of transaminases were compared between two groups of patients: 10 HIV/HCV-coinfected patients with persistently undetectable HIV viremia (group A) and 12 HIV/HCV-coinfected patients with persistent detectable HIV viremia. No difference was detected in HCV viral load in either group. An increase in transaminases was found only in patients with persistent undetectable HIV viral load, which was correlated with the increase in CD8+ T cells. This may suggest that the restoration of CD8+ T cell cytotoxicity could lead to an enhancement of hepatitis C-related disease in HCV/HIV-coinfected patients receiving HAART.     

Relationship between drug resistance and HIV-1 disease progression or death in patients undergoing resistance testing

OBJECTIVE: To evaluate factors associated with drug resistance detected by genotypic antiretroviral resistance testing (GART), and to determine the association between the level of resistance and subsequent human immunodeficiency type 1 (HIV-1) disease progression or death. DESIGN: Observational cohort study. METHODS: We identified highly active antiretroviral therapy (HAART)-treated patients who had GART as part of clinical management. Factors associated with greater numbers of resistance mutations were assessed by ordinal logistic regression. Survival analysis was used to assess time to a new opportunistic condition or death following GART. RESULTS: A total of 572 patients were identified who had GART: of these, 50% had 0-2 resistance mutations, 33% had 3-6 mutations, and 17% had >/= 7 mutations. In multivariate analysis, prolonged use of HAART in the setting of incomplete viral suppression was significantly associated with more drug resistance. Patients with fewer resistance mutations were significantly more likely to achieve viral suppression after GART than patients with more mutations. Compared to patients with two or less resistance mutations, those with three to six mutations, or seven or more mutations were not at higher risk of HIV-1 disease progression or death over a median follow-up of 15 months. In contrast, continued HAART use following GART was strongly associated with slower disease progression, particularly at lower CD4 cell counts. CONCLUSION: These results support the hypothesis the drug-resistant HIV-1 may be less pathogenic than wild-type virus, and that continued use of HAART might provide clinical benefit, despite persistent viremia and HIV-1 drug resistance.     

Hepatitis C virus activation in HIV-infected patients initiating highly active antiretroviral therapy

We describe repeated episodes of hepatitis C (HCV) activation associated with initiation of highly active antiretroviral therapy (HAART) in two HIV/HCV coinfected individuals with undetectable serum HCV RNA. Both patients developed high HCV viremia (>1 million IU/mL) and elevations in aminotransferases >10 times upper limit of normal) within 4 months of starting HAART. This is the first report of clinically significant HCV activation in HCV-seropositive patients with initially undetectable HCV viremia. These observations suggest that flares of hepatitis C in the setting of the immune reconstitution inflammatory syndrome can occur even in those patients who have undetectable serum HCV levels prior to HAART initiation.     

CD4+ T cell recovery beyond the first year of complete suppression of viral replication during highly active antiretroviral therapy is not influenced by CD8+ T cell activation

CD38 expression on CD8(+) T cells was longitudinally assessed in 31 human immunodeficiency virus (HIV)-infected persons with undetectable plasma viremia who had undergone highly active antiretroviral therapy (HAART) for 12 months and were followed for a mean of 30 months thereafter. Overall, CD4(+)T cell counts increased during follow-up, whereas CD38 expression remained stable. However, a subset of patients showed declines in CD38 expression, and, conversely, another subset showed increases in CD38 expression. No association could be found between long-term gains in CD4(+) T cells and evolution of CD38 expression. Thus, activation of CD8(+) T cells does not seem to be associated with the extent of CD4(+) T cell recovery beyond the first year of successful HAART.     

Persistence of distinct HIV-1 populations in blood monocytes and naive and memory CD4 T cells during prolonged suppressive HAART

OBJECTIVE: Reservoirs of HIV-1 are a major obstacle to virus eradication. There is therefore a need to clearly understand the molecular nature of the virus populations that persist in patients with sustained suppression of plasma viraemia on highly active antiretroviral therapy (HAART). DESIGN: We performed a detailed analysis of the genotypes of HIV-1 quasispecies isolated from highly purified blood cell types taken from three selected patients with sustained undetectable viral loads on HAART for 7 years. METHODS: We used polychromatic flow cytometry to sort naive and memory CD4 T cells, CD14 monocytes, and CD56+CD3- natural killer (NK) cells from the total peripheral blood mononuclear cells after 7 years of HAART. Clonal analysis was used to determine coreceptor use and drug-resistance genotypes of HIV-1 quasispecies in the sorted blood cell types. RESULTS: We detected HIV-1 DNA in memory and naive CD4 T cells and in CD14 monocytes, but not in the CD56+CD3- NK cells. Phylogenetic analysis demonstrated that the various blood cells types of two of the three patients harboured genetically distinct HIV-1 quasispecies. Drug-resistance mutations were also distributed differently from one cell type to another. This compartmentalization suggests a minimal virus trafficking between blood cell types during suppressive HAART. CONCLUSIONS: We observed a cell-specific compartmentalization of the residual virus populations during prolonged suppressive HAART. The coexistence of numerous HIV-1 quasispecies with different resistance genotypes and coreceptor use in cellular reservoirs may be relevant for future antiretroviral treatment strategies.     

Presence of an inducible HIV-1 latent reservoir during highly active antiretroviral therapy

Although highly active antiretroviral therapy (HAART) in the form of triple combinations of drugs including protease inhibitors can reduce the plasma viral load of some HIV-1-infected individuals to undetectable levels, it is unclear what the effects of these regimens are on latently infected CD4⁺ T cells and what role these cells play in the persistence of HIV-1 infection in individuals receiving such treatment. The present study demonstrates that highly purified CD4⁺ T cells from 13 of 13 patients receiving HAART with an average treatment time of 10 months and with undetectable (<500 copies HIV RNA/ml) plasma viremia by a commonly used bDNA assay carried integrated proviral DNA and were capable of producing infectious virus upon cellular activation in vitro. Phenotypic analysis of HIV-1 produced by activation of latently infected CD4⁺ T cells revealed the presence in some patients of syncytium-inducing virus. In addition, the presence of unintegrated HIV-1 DNA in infected resting CD4⁺ T cells from patients receiving HAART, even those with undetectable plasma viremia, suggests persistent active virus replication in vivo.     

Virologic and immunologic outcomes after 24 weeks in HIV type 1-infected adolescents receiving highly active antiretroviral therapy

BACKGROUND: Adolescents represent the fastest growing demographic group of new human immunodeficiency virus (HIV) infections in the United States. At present, there is little information available about their response to therapy. METHODS: We studied 120 adolescents infected via high-risk behaviors who began receiving highly active antiretroviral therapy (HAART), to determine their virologic and immunologic response to therapy. RESULTS: Subjects were enrolled at 28 sites of the Pediatric Acquired Immunodeficiency Syndrome Clinical Trials Group. After 16-24 weeks of HAART, 59% of subjects had reproducible undetectable virus loads, according to repeat measurements (virologic success). As enumerated by flow-cytometric analysis, increases in levels of CD4 helper cells (both naive and memory) and decreases in levels of CD8 suppressor cells were observed. Partial restoration of some immunologic parameters for patients who did not achieve virologic success was also observed, but to a more limited extent than for adolescents with virologic success. Adherence to HAART was the only predictor of achieving undetectable virus loads. CONCLUSIONS: Adolescents have the capacity to improve their immunologic status with HAART. Lower than expected success in virologic control is related to lack of adherence, and efforts to improve treatment outcome must stress measures to assure adherence to medication.     

High levels of drug-resistant human immunodeficiency virus variants in patients exhibiting increasing CD4+ T cell counts despite virologic failure of protease inhibitor-containing antiretroviral combination therapy

The genotypic mutations associated with indinavir resistance were analyzed in 27 patients who exhibited sustained CD4+ T cell responses to highly active antiretroviral therapy (HAART), despite virologic failure of treatment. After 12 months of HAART, 1 or 2 primary resistance mutations had occurred in 18 (66%) of the patients, and secondary mutations had accumulated in 22 (88%) of the patients. The number and patterns of mutations in the patients who exhibited discrepant responses to HAART did not differ from those observed in patients who exhibited immunologic and virologic failure to therapy. Results indicate that many patients have prolonged immunologic benefits, despite the development of virologic failure and protease inhibitor mutations. The clinical course of this group of patients calls into question the relevance of genotypic resistance and plasma human immunodeficiency virus RNA level as surrogate markers in patients receiving HAART.     

Evaluation of lymph node virus burden in human immunodeficiency virus-infected patients receiving efavirenz-based protease inhibitor--sparing highly active antiretroviral therapy

Although efavirenz-containing regimens effectively suppress plasma levels of human immunodeficiency virus (HIV) RNA, it is now clear that undetectable plasma viremia may not reflect a lack of viral replication. Because lymphoid tissue is an active site of HIV replication, the lymph node virus burden was analyzed in persons who received highly active antiretroviral therapy (HAART) containing either efavirenz or a protease inhibitor (PI). Testing with in situ hybridization revealed no detectable follicular dendritic cell-associated HIV RNA in either group, and only 2 of 8 persons in the efavirenz group and 1 of 4 in the PI group had detectable RNA in lymph node mononuclear cells (LNMC) when tested by use of nucleic acid sequencebased amplification. Low levels of replication-competent HIV were identified in both groups by use of quantitative coculture assays. There was no evidence of development of resistance to either regimen in virus isolated from LNMC. These data support the use of efavirenz as an alternative to a PI in initial HAART regimens.     

Longitudinal assessment of immune response and viral characteristics in HIV-infected patients with prolonged CD4(+)/viral load discordance

Although suppression of HIV-1 RNA below the limit of detection is associated with optimal outcomes, many patients can maintain or increase their CD4(+) count for prolonged time periods in the presence of persistent low-level viremia. We followed seven patients with prolonged (>5 years) discordant CD4(+)/viral load (VL) responses on protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) prospectively for 1 year to assess evolution of immune function, viral phenotype, replication capacity (RC), and resistance profile. Immune function was assessed by qualitative and quantitative measurement of cellular activation (CD38(+)HLA-DR(+) and CD38 antibodies bound per cell), and the interferon (IFN)-() ELISpot assay. Presence of syncytium-inducing (SI) or nonsyncytium-inducing (NSI) viral strains was determined by MT-2 cell culture. RC was measured by a modified rapid recombinant virus assay. The resistance profile was characterized by both genotypic and phenotypic analysis. Over the year of follow-up, IFN-() production to gag persisted, responses to other HIV antigens increased, and markers of cellular activation did not change. NSI virus predominated. The genotypic (GSS) and phenotypic (PSS) susceptibility scores remained stable. Evolution of RC was variable over the year of follow-up, but the RC of viruses remained well below that of wild-type clinical isolates. Thus, CD4(+)/VL discordance can be maintained for periods exceeding 5 years in some patients receiving PI-based HAART without significant evolution of HIV resistance.     

No evidence of an association between transient HIV viremia ("Blips") and lower adherence to the antiretroviral medication regimen

BACKGROUND: Transient human immunodeficiency virus (HIV) viremia, a common phenomenon among patients taking antiretroviral therapy, is often attributed to lapses in adherence to the medication regimen. We investigated this relationship in a prospective observational cohort of 128 patients initiating a new regimen. METHODS: A case of transient viremia was defined as an HIV RNA level of 40-1000 copies/mL ("blip") sandwiched between 2 months of HIV RNA levels <40 copies/mL ("pre" and "post"). Adherence was most often measured with a composite adherence score (CAS), which is primarily based on electronically measured adherence. Case subjects' adherence and dose-timing was compared with (1) that of other patients (control subjects), who had undetectable virus loads for 3 consecutive months, and (2) that during periods of sustained undetectable virus loads among the case subjects themselves, if available. RESULTS: Among the 28 case subjects, mean CAS-measured adherence did not decrease before transient viremia; adherence during the pre, blip, and post periods were 86%, 84%, and 80%, respectively. Control subjects had lower adherence levels during the corresponding 3 months (77%, 79%, and 75%, respectively; P = .046). Among the 19 patients able to serve as their own controls, CAS-measured adherence was higher during the period of transient viremia than during control periods (P = .01). Similar relationships were found when comparing only electronically measured adherence on a week-wise basis. There were no significant differences in dose-timing error between case subjects and control subjects. CONCLUSIONS: We found no evidence that transient HIV viremia is associated with decreases in adherence or differences in dose-timing. Other etiologies for transient viremia should be evaluated.     

Prospective comparison of first-line nelfinavir therapy versus nelfinavir introduction in rescue antiretroviral regimens

In order to establish the role of the protease inhibitor nelfinavir in current clinical practice, a prospective 18-month open-label comparison of efficacy and tolerability of nelfinavir was performed among HIV-infected patients who either incorporated nelfinavir in their first-line highly active antiretroviral therapy (HAART) regimen (group A, 57 patients), or who added nelfinavir to a rescue antiretroviral regimen (following at least two attempts with protease inhibitor-based HAART) (group B, 67 patients). All evaluable data were analyzed according to the prior and concurrent antiretroviral therapy, including genotypic resistance assays for patients undergoing salvage therapy. A significantly better virologic outcome (as expressed by a > 2 log(10) drop of plasma viremia versus baseline or attainment of undetectable levels), was shown among patients belonging to group A versus group B, where a number of genotypic mutations possibly elicited by previous anti-HIV treatment strongly impaired a potent and sustained nelfinavir activity. On the whole, the immunologic response (as expressed by the mean CD4(+) lymphocyte count versus baseline), substantially paralleled the virologic one in all analyzed subgroups, but a tendency toward a maintained immunologic competence was also observed in the majority of patients experiencing virologic failure. Nelfinavir introduction was sufficiently safe, because a limited percentage of patients suffered from mild-to-moderate, novel, or continuing adverse events, which proved significantly more frequent in the salvage group but did not affect adherence to HAART.     

Antiretroviral resistance during successful therapy of HIV type 1 infection

HIV type 1 (HIV-1) drug resistance mutations were selected during antiretroviral therapy successfully suppressing plasma HIV-1 RNA to <50 copies/ml. New resistant mutant subpopulations were identified by clonal sequencing analyses of viruses cultured from blood cells. Drug susceptibility tests showed that biological clones of virus with the mutations acquired during successful therapy had increased resistance. Each of the five subjects with new resistant mutants had evidence of some residual virus replication during highly active antiretroviral therapy (HAART), based on transient episodes of plasma HIV-1 RNA > 50 copies/ml and virus env gene sequence changes. Each had received a suboptimal regimen before starting HAART. Antiretroviral-resistant HIV-1 can be selected from residual virus replication during HAART in the absence of sustained rebound of plasma HIV-1 RNA.     

Recent origin of human immunodeficiency virus type 1 variants in resting CD4+ T lymphocytes in untreated and suboptimally treated subjects.

Resting CD4(+) T lymphocytes are an important reservoir for human immunodeficiency virus type 1 (HIV-1) in treated patients with undetectable viremia. The knowledge of viral persistence in these cells is limited, however, for patients without treatment or patients for whom treatment is failing; therefore, this reservoir in such patients was characterized. Virus variants were characterized in 3 subjects who were followed-up from primary HIV-1 infection and 5 treatment-experienced subjects. No founder viral sequences and only a minority of the earlier identified drug-induced mutations were found in the resting T lymphocytes. Instead, the viral sequences were closely related to those detected simultaneously in plasma, except in 2 treatment-experienced subjects. Thus, a turnover and replenishment of this virus reservoir in peripheral blood is likely to occur in most persons with detectable viremia. However, infrequently the virus variants in plasma and resting T cells seem to be derived from independent sources.