Diagnosis of antiretroviral therapy failure in Malawi: poor performance of clinical and immunological WHO criteria

Objectives  In antiretroviral therapy (ART) scale-up programmes in sub-Saharan Africa viral load monitoring is not recommended. We wanted to study the impact of only using clinical and immunological monitoring on the diagnosis of virological ART failure under routine circumstances.
Methods  Clinicians in two urban ART clinics in Malawi used clinical and immunological monitoring to identify adult patients for switching to second-line ART. If patients met clinical and/or immunological failure criteria of WHO guidelines and had a viral load <400 copies/ml there was misclassification of virological ART failure.
Results  Between January 2006 and July 2007, we identified 155 patients with WHO criteria for immunological and/or clinical failure. Virological ART failure had been misclassified in 66 (43%) patients. Misclassification was significantly higher in patients meeting clinical failure criteria (57%) than in those with immunological criteria (30%). On multivariate analysis, misclassification was associated with being on ART <2 years [OR = 7.42 (2.63, 20.95)] and CD4 > 200 cells/μl [OR = 5.03 (2.05, 12.34)]. Active tuberculosis and Kaposi's sarcoma were the most common conditions causing misclassification of virological ART failure.
Conclusion  Misclassification of virological ART failure occurs frequently using WHO clinical and immunological criteria of ART failure for poor settings. A viral load test confirming virological ART failure is therefore advised to avoid unnecessary switching to second-line regimens.     

Immunological and virological impact of highly active antiretroviral therapy initiated during acute HIV-1 infection

The immunological and virological impact of short-term treatment initiated during acute human immunodeficiency virus type 1 (HIV-1) infection was assessed prospectively in 20 subjects, 12 of whom initiated highly active antiretroviral therapy (HAART) for 24 weeks and then terminated treatment. Treatment resulted in suppression of viremia, an increase in the CD4+ T cell count, enhanced differentiation of HIV-1-specific CD8(+) T cells from effector memory to effector cells at week 24 of HAART, and significantly higher virus-specific interferon- gamma+ CD8+ T cell responses after viral rebound (at week 48). However, despite these immunological changes, no differences in viremia or in the CD4+ T cell count were found 6 months after HAART was stopped, when treated subjects were compared with untreated subjects.     

Immunological and virological study of enfuvirtide-treated HIV-positive patients

OBJECTIVE: To evaluate the predictive value and evolution of immunological and virological parameters related to HIV entry and pathogenesis in patients receiving enfuvirtide (ENF) plus an optimized regimen. METHODS: A phase III clinical trial substudy of ENF in 22 patients measured virus coreceptor use and sensitivity to ENF, levels of chemokines, cytokines and chemokine receptors, CD38 and HLA-DR expression as markers of T cell activation and ex vivo cell death at baseline and at week 32. RESULTS: Treatment including ENF reduced HIV viral load (P < 0.001) and increased the CD4 cell count in patients that responded (RP) to treatment (n = 14). Significant (P < 0.05) increases were noted in the RP group in CXCR4 and CCR5 expression in CD4 cells without major differences in chemokine and interleukin-7 levels. A decrease in CD38 expression in the absence of HLA-DR changes was observed in CD4 cells. Apoptosis of peripheral blood mononuclear cells was significantly reduced in the RP group. Coreceptor use or ENF sensitivity of virus isolated at baseline was not associated with virus resistance or response to treatment, which appeared to be related to the activation state (HLA-DR expression) of CD4 cells at baseline. CONCLUSION: The outcome of ENF-containing treatment could not be associated with HIV coreceptor use at baseline. CD4 cell activation and viral drug resistance were the only markers of treatment response. Changes induced by ENF-containing regimen were seen in HIV coreceptor expression, including an increase in CCR5+CD4+ cells, a decrease in CD38 T cells and a concomitant reduction of T cell apoptosis.     

Immunological and virological responses to highly active antiretroviral therapy in a non-clinical trial setting in a developing Caribbean country

OBJECTIVE: Few data exist on the efficacy of antiretroviral therapy in individuals infected with HIV in the Caribbean. We evaluated the virological and immunological responses of HIV-infected adults starting highly active antiretroviral therapy (HAART). DESIGN: This was a prospective observational cohort study. METHODS: A total of 158 antiretroviral-naive patients who initiated HAART between January 2002 and March 2003, and completed at least 6 months of treatment and follow up, were included in the analysis. The response to therapy was assessed by changes in CD4 cell counts and viral loads from baseline. The mean increase in CD4 cell count, the rate of virological success (a viral load of <50 HIV-1 RNA copies/mL) and the rate of immunological success (an increase in CD4 cell count of > or =50 cells/microL over the baseline value) after commencing HAART were measured. RESULTS: In total, 82% of patients (123 of 150) achieved viral loads of <50 copies/mL after 6 months of therapy. Viral success rate after 6 months of HAART was similar irrespective of gender, pre-HAART CD4 cell count and pre-HAART viral load. However, patients older than 40 years were significantly more likely to achieve virological success than those younger than 40 years. At 6 months after starting HAART, 79.5% of patients were estimated to have achieved immunological success and 17.9% had an increase in CD4 cell count of > or =200 cells/microL over the baseline value. The median increase in CD4 cell count for the 156 patients who had CD4 cell counts at baseline and at 6 months of therapy was 122 cells/microL. CONCLUSION: In this cohort of antiretroviral-naive HIV-infected adults, there was a high rate of virological and immunological success after 6 months of HAART, irrespective of the pre-HAART viral load and CD4 cell count.     

Human immunodeficiency virus 1 protease inhibitors in clinical practice: predictors of virological outcome.

OBJECTIVES: To ascertain whether prolonged suppression of viral replication can be achieved in clinical practice and to identify factors associated with virological outcome. DESIGN: Retrospective observational study. SETTING: University-affiliated human immunodeficiency virus (HIV) clinic in Cleveland, Ohio. PARTICIPANTS: Patients treated with regimens that included protease inhibitors between June 1995 and December 1997. We identified 366 patients; 310 had sufficient virological follow-up data to be included. MAIN OUTCOME MEASURE: Virological success was defined as plasma HIV-RNA levels lower than 400 copies/mL at the last clinic visit. Virological failure was subdivided according to the maximum degree of suppression of viral replication achieved. Multivariate analysis was performed to identify baseline factors associated with virological outcome. RESULTS: Virological success was achieved by 47% of patients at a median follow-up of 335 days. The median CD4+ cell count increase and HIV-RNA level decrease were 0.10x10(9)/L (100 cells/microL) and greater than 1.3 log10 in patients who achieved virological success, and 0.010x10(9)/L and 0.32 log10 for those who did not. In multivariate analysis the likelihood of virological success was diminished in women (P<.02) and in patients who missed 2 or more clinic visits in the prior year (P<.001), and decreased when the regimen was started earlier (P<.04). Patients with a lower nadir CD4+ cell count (P<.04) and higher peak plasma HIV-RNA levels (P<.001) also had a decreased likelihood of virological success. CONCLUSIONS: More than half the patients who started a regimen that included protease inhibitors in an academic clinical practice failed to achieve durable suppression of viral replication and also experienced a poorer immunologic outcome as determined by CD4+ cell count increase. Missed clinic visits, more advanced disease, and higher plasma HIV-RNA levels may predict failure.     

CCR5Delta32 and promoter polymorphisms are not correlated with initial virological or immunological treatment response.

OBJECTIVE: Natural genetic polymorphisms within the CCR5 gene and promoter have been linked to patterns of HIV-1 clinical disease progression in untreated individuals. The objective of this retrospective study was to assess the influence of the CCR5Delta32 mutation and promoter polymorphisms on virological and immunological treatment outcome in 436 antiretroviral-naive individuals initiating their first therapy, over a mean follow-up time of 22 months. METHODS: Genotypes for the CCR5Delta32 and promoter were determined by polymerase chain reaction amplification of human DNA from plasma, followed by gel electrophoresis for CCR5Delta32 or DNA sequencing for the promoter polymorphisms. Time to virological failure [defined as the second plasma viral load > or = 400 copies HIV-1 RNA/ml) and immunological failure (defined as time to achieve two successive CD4 cell counts below baseline) were analyzed by Kaplan-Meier methods. RESULTS: The five most common CCR5 promoter polymorphisms were observed at positions 208(G/T), 303(A/G), 627(C/T), 676(A/G), and 927(C/T). Allele frequencies were 0.24(208T), 0.38(303G), 0.44(627T), 0.35(676G) and 0.18(927T). The CCR5Delta32 allele frequency was 0.08. The promoter polymorphisms existed in strong linkage disequilibrium with each other and the Delta32. No significant effect of the individual CCR5Delta32 or promoter polymorphisms could be demonstrated with respect to time to treatment failure as defined by virological or immunological parameters (P > or = 0.07). Similarly, when combined CCR5Delta32 and promoter genotypes were analyzed in order to account for linkage disequilibrium, no significant effect was observed on time to virological or immunological failure (P > 0.6). CONCLUSION: CCR5Delta32 and promoter genotypes may not be of clinical relevance in predicting initial virological or immunological response to antiretroviral therapy.     

Immune restoration does not invariably occur following long-term HIV-1 suppression during antiretroviral therapy. INCAS Study Group

BACKGROUND: Current antiretroviral treatment can induce significant and sustained virological and immunological responses in HIV-1-infected persons over at least the short- to mid-term. OBJECTIVES: In this study, long-term immune reconstitution was investigated during highly active antiretroviral therapy. METHODS: Patients enrolled in the INCAS study in The Netherlands were treated for 102 weeks (range 52-144 weeks) with nevirapine (NVP) + zidovudine (ZDV) (n = 9), didanosine (ddl) + ZDV (n = 10), or NVP + ddl + ZDV (n = 10). Memory and na?ve CD4+ and CD8+ T cells were measured using CD45RA and CD27 monoclonal antibodies (mAb), T-cell function was assayed by CD3 + CD28 mAb stimulation, and plasma HIV-1 RNA load was measured by ultra-direct assay (cut-off < 20 copies/ml). RESULTS: Compared to both double combination regimens the triple combination regimen resulted in the most sustained increase in CD4+ T cells (change in CD4+, + 253 x 10(6) cells/l; standard error, 79 x 10(6) cells/l) and reduction of plasma HIV-1 RNA. In nine patients (31%) (ddl + ZDV, n = 2; NVP + ddl + ZDV, n = 7) plasma HIV-1 RNA levels remained below cut-off for at least 2 years. On average, these long-term virological responders demonstrated a significantly higher increase of na?ve and memory CD4+ T cells (P = 0.01 and 0.02, respectively) as compared with patients with a virological failure, and showed improved T-cell function and normalization of the na?ve; memory CD8+ T-cell ratio. However, individual virological success or failure did not predict the degree of immunological response. T-cell patterns were independent of baseline CD4+ T-cell count, T-cell function, HIV-1 RNA load or age. Low numbers of na?ve CD4+ T cells at baseline resulted in modest long-term na?ve T-cell recovery. CONCLUSIONS: Patients with prolonged undetectable plasma HIV-1 RNA levels during antiretroviral therapy do not invariably show immune restoration. Na?ve T-cell recovery in the setting of complete viral suppression is a gradual process, similar to that reported for immune recovery in adults after chemotherapy and bone marrow transplantation.     

Disease progression in patients with virological suppression in response to HAART is associated with the degree of immunological response

OBJECTIVE: To determine if immunological response is associated with disease progression in patients with virological suppression after initiating HAART. DESIGN: A cohort study of 1084 treatment-naive participants in the British Columbia HIV/AIDS Drug Treatment Program who had achieved viral loads < 500 copies/ml at 3-9 months after initiating triple-drug therapy. METHODS: Cox proportional hazards was used to model the association with disease progression of baseline variables, change in CD4 cell counts and CD4 cell count strata at 6 months. Logistic regression analysis was used to examine associations with two definitions of poor immunological response. RESULTS: Patients were followed for a median of 51.4 months. In univariate analyses, increases in CD4 cell counts of < 25 cells/microl and absolute CD4 cell counts of < 200 cells/microl were associated with an increased risk of death or new AIDS events. Two mulitivariate models, one including baseline CD4 cell count and change in CD4 cell count from baseline and the other including only absolute CD4 cell counts at 6 months, were found to predict disease progression in this setting. Increases in CD4 cell count of < 25 cells/microl were associated with increasing age and inversely associated with low baseline CD4 cell counts, high baseline viral loads and good adherence to therapy. CD4 cell counts of < 200 cells/microl at 6 months were associated with low baseline CD4 cell counts and having AIDS at baseline. CONCLUSION: Patients with virological suppression are still at risk for HIV disease progression if adequate immunological responses are not achieved.     

Long-term efficacy and safety of ritonavir/indinavir at 400/400 mg twice a day in combination with two nucleoside reverse transcriptase inhibitors as first line antiretroviral therapy

Objective To determine the long‐term antiretroviral efficacy and tolerability of dual protease inhibitor (PI) therapy with indinavir (IDV)/ritonavir (RTV) at 400/400 mg twice a day (BID) in combination with two nucleoside reverse trancriptase inhibitors (NRTIs).
Design and methods In an open‐label, uncontrolled multicentre clinical trial, antiretroviral therapy naive patients ( n  = 93) with a high median baseline HIV‐1 RNA level of 210 000 copies/mL (range 17 000–2 943 000) and a median CD4 cell count of 195 copies/µL (range 4–656 copies/µL) were started on a regimen of either zidovudine (ZDV)/lamivudine (3TC) (49%), stavudine (d4T)/3TC (38%) or d4T/didanosine (ddI) (14%) plus RTV and IDV, each at 400 mg BID. CD4 cell counts and HIV RNA were determined at 4‐week intervals for a duration of 72 weeks. Statistical analysis was performed on treatment as well as by intent to treat, where missing values were counted as failures.
Results HIV RNA levels below the limit of detection were achieved in 59.5% (< 80 copies/mL) and 63% (< 500 copies/mL) of patients according to the intent to treat analysis at week 72. In the on treatment analysis, the proportion of patients reaching an undetectable viral load was 94.5% (< 80 copies/mL) and 100% (< 500 copies/mL), respectively. Apart from diarrhoea and nausea, serum lipid abnormalities were identified as the most prominent adverse reaction. No cases of nephrotoxicity occurred during the entire observation period of 72 weeks.
Conclusions Our results demonstrate that quadruple therapy with RTV/IDV and two NRTIs induces potent, durable and safe HIV suppression and might be particularly beneficial as a first line therapy for patients with a high baseline viral load.     

No association between GB virus-C viremia and virological or immunological failure after starting initial antiretroviral therapy

INTRODUCTION: Co-infection with GBV-C ('Hepatitis G' virus) appears to be associated with slower disease progression in HIV-infected, untreated individuals. We wished to determine whether detection of GBV-C RNA was associated with differential response to HIV therapy in a population-based cohort of 461 individuals initiating antiretroviral therapy between June 1996 and August 1998, in British Columbia, Canada. METHODS: The presence of GBV-C RNA in plasma was identified by nested RT-PCR, using detection of HIV RNA as a positive control. Time to virological success [achieving HIV plasma viral load (pVL) < or = 500 copies/ml], virological failure (subsequent confirmed pVL > 500 copies/ml) and immunological failure (confirmed CD4 cell count below baseline) were assessed by Kaplan-Meier methods and Cox proportional hazard regression. RESULTS: Of the 441 individuals for whom results were available, 90 (20.4%) had detectable plasma GBV-C RNA. GBV-C RNA was significantly associated with a lower HIV pVL at baseline (P = 0.004). In univariate and multivariate Cox models, GBV-C RNA positive and negative individuals did not differ with respect to time to virological success [risk ratio (RR), 0.98; 95% confidence interval (CI), 0.75-1.27], time to virological failure (RR, 1.10; 95% CI, 0.74-1.65), or time to immunological failure (RR, 1.09; 95% CI, 0.73-1.63). There was no correlation between detection of GBV-C RNA and mutations in the human chemokine receptors CCR5 and CX CR1, or HIV viral tropism as predicted by the HIV envelope sequence (P > 0.1). CONCLUSION: GBV-C viremia is relatively common in individuals seeking treatment for HIV infection; however, it does not appear to have any effect on initial antiretroviral therapy response.     

The effects of an HIV-1 immunogen (Remune) on viral load, CD4 cell counts and HIV-specific immunity in a double-blind, randomized, adjuvant-controlled subset study in HIV infected subjects regardless of concomitant antiviral drugs

Objective   We examined the activity of an HIV-1 immunogen (Remune) on viral load, CD4 cells and HIV-1 specific immunity.
Methods   Plasma and peripheral blood mononuclear cells were obtained in a predefined random subset of subjects ( n  = 252) from a multicentre, double-blind, adjuvant-controlled phase III clinical endpoint study.
Results   The subjects treated with the HIV-1 immunogen had a significantly greater decline in viral load at multiple time points ( P  < 0.05), a trend towards increased CD4+ T cell counts and significantly enhanced HIV-1 specific immune responses as measured by HIV-1 lymphocyte proliferation ( P  < 0.001) compared to the adjuvant control group. Furthermore, in the HIV-1 immunogen treated group, enhanced HIV-1 specific lymphocyte proliferative immune responses were associated with decreased HIV-1 plasma RNA.
Conclusion   These results suggest that, in a predefined, random subset of subjects, a beneficial effect of the HIV-1 immunogen was observed on viral load, CD4+ T cells, and HIV-specific immunity. These differences were observed in a background of multiple drug therapies. Ongoing trials are evaluating the effect of the combination of this HIV-1 specific, immune-based therapy with potent antiviral drug therapy on virological outcomes.     

Success and failure of virus-specific T cell responses in hepatitis C virus infection

Hepatitis C virus (HCV) infection is only cleared in a minority of infected individuals, the majority of patients develop chronic infection. Chronic HCV infection potentially leads to liver fibrosis, cirrhosis and finally hepatocellular carcinoma. The host immune response is an important determinant in the outcome of HCV infection. Innate as well as adaptive cellular and humoral immune responses mediate important antiviral actions; however, virus-specific T cell responses appear to be most critical. Indeed, strong and multispecific CD4+ as well as CD8+ T cell responses are required for viral clearance. Interestingly, individuals who express certain HLA alleles (which are important for antigen presentation to CD4+ and CD8+ T cells) have a higher chance to clear the virus. The mechanisms of protection by HLA class I alleles such as HLA-B27 have been characterized recently. In most individuals, however, the HCV-specific immune response fails to clear the virus. Several mechanisms underlying this HCV-specific T cell failure have been identified. These include viral factors such as viral escape mutations and immunological factors such as the expression of inhibitory receptors, which lead to CD8+ T cell dysfunction. An in-depth understanding of the determinants of success or failure of the HCV-specific T cell response is critical for the development of prophylactic as well as therapeutic vaccination regimes against HCV. Here, we will discuss the virological and immunological determinants of HCV clearance and persistence.     

Long-term immunological response in HIV-1-infected subjects receiving potent antiretroviral therapy

OBJECTIVE: To determine the long-term T-lymphocyte response to highly active antiretroviral therapy (HAART) and to define predictors of the immunological response. DESIGN: Cohort study, including 135 HIV-1-infected subjects at a city general practice who commenced HAART between 1996 and 1998. METHODS: Collection of plasma HIV-1 RNA, CD4+ and CD8+ T-lymphocyte data at 3-6 monthly time intervals over 2 years. RESULTS: Seventy-three subjects (54%) achieved suppression of plasma HIV-1 RNA to levels below 400 copies/ml during the observation period, 31 individuals (23%) had detectable plasma HIV-1 RNA below 10,000 copies/ml and 31 subjects (23%) had virological failures with viral loads above 10,000 copies/mL. Median CD4+ T lymphocytes increased from 246 to 463 x 10(6) cells/l, showing a median rise of 20 x 10(6) cells/l per month in the first 3 months and 7 x 10(6) cells/l per month thereafter. The proportion of individuals who reached CD4+ cell counts above 500 x 10(6) cells/l increased from 8% at baseline to 54% at 2 years. Treatment-na?ve individuals, subjects with a large reduction of HIV-1 RNA or a large early CD8+ increase had better early CD4+ responses. Long-term CD4+ T-cell increases were inversely correlated with mean plasma HIV-1 RNA levels. Baseline CD4+ T-cell count was the most important determinant of reaching CD4+ cell counts above 500 x 10(6) cells/l. Nineteen per cent of subjects had no further CD4+ T-cell increases in the second year of therapy despite undetectable viral load. CONCLUSIONS: Immune reconstitution is a slow process, showing a large individual variability. The virological response to HAART was the most important determinant of the immunological short- and long-term response.     

Prolonged CD4+ cell/virus load discordance during treatment with protease inhibitor-based highly active antiretroviral therapy: immune response and viral control

Mechanisms that underly discordant CD4+ cell/virus load (VL) responses in patients who receive highly active antiretroviral therapy (HAART) were studied in 30 human immunodeficiency virus (HIV)-positive patients, in 3 groups. Discordant responders maintained CD4+ cell levels >200/mm(3) with stable or increasing trend, despite sustained VLs of 500-5000 copies/mL, for >2 years. Treatment-success patients had CD4+ cell counts >200/mm(3) with stable or increasing trend and VLs <50 copies/mL, for >2 years. Treatment-failure patients initially responded to HAART, followed by decreasing CD4+ cell counts and increasing VLs. Interferon-gamma production to gag and noncytolytic CD8+ cell suppressive activity were greater in discordant responders. Cellular activation was greatest in patients with treatment failure. All discordant responders had non-syncytium-inducing (CCR5-tropic) viruses. Viruses from discordant responders and from patients with treatment failure had extensive resistance mutations; discordant responders had significantly lower viral replication capacities. These findings suggest that discordant responses may be related to enhanced HIV-directed immune responses, diminished cellular activation, decreased viral replication capacity, and preservation of non-syncytium-inducing virus strains.     

Patterns of CD8 T cell clonal dominance in response to change in antiretroviral therapy in HIV-infected children

OBJECTIVE: To examine the influence of change in antiretroviral therapy (ART) on patterns of CD8 T cell clonal dominance in HIV-infected children. Design: Seventeen HIV-infected children with plasma virus loads between 3.1 and 5.7 log10 were investigated before and after changes in ART. METHODS: CDR3 spectratyping was performed in 22 T cell receptor (TCR) Vbeta subfamilies by multiplex polymerase chain reaction (PCR) in purified peripheral blood CD8 T cells in conjunction with CD4 cell counts, plasma HIV-RNA copies and lymphoproliferative assays (LPA). RESULTS: CD8 T cell clonal dominance in two or more Vbeta families was present in eight out of 17 children. After a change in therapy, 13 patients (76%) acquired new clones whereas three patients (17.6%) showed a loss in CD8 cell clones. An increase in the numbers of dominant clones correlated with an increase in percentage CD4 cell counts (P < 0.001) and with improved LPA responses to tetanus (P < 0.05) and alloantigens (P < 0.01). CD4 cell increase was associated with an initial mean gain of 3.1+/-2.1 CD8 cell clones, independent of a virological response. A loss of CD8 cell clones or failure to achieve CD4 T cell increase was associated with failure to achieve virological suppression. CONCLUSION: Children with chronic HIV infection manifest CD8 T cell clonal dominance, which appears to be dependent upon the adequacy of the CD4 cells. With optimization of therapy, a gain in clonal dominance is the predominant response, except in situations of failure to contain viral replication.