The HIV RNA setpoint theory revisited.

BACKGROUND: The evolution of plasma viral load after HIV infection has been described as reaching a setpoint, only to start rising again shortly before AIDS diagnosis. In contrast, CD4 T-cell count is considered to show a stable decrease. However, characteristics of marker evolution over time depend on the scale that is used to visualize trends. In reconsidering the setpoint theory for HIV RNA, we analyzed the evolution of CD4 T-cell count and HIV-1 RNA level from HIV seroconversion to AIDS diagnosis. Follow-up data were used from two cohort studies among homosexual men (N = 400), restricting to the period before highly active antiretroviral therapy became widely available (1984 until 1996). Individual trajectories of both markers were fitted and averaged, both from seroconversion onwards and in the four years preceding AIDS diagnosis, using a bivariate random effects model. Both markers were evaluated on a scale that is directly related to AIDS risk. RESULTS: Individuals with faster AIDS progression had higher HIV RNA level six months after seroconversion. For CD4 T-cell count, this ordering was less clearly present. However, HIV RNA level and CD4 T-cell count showed qualitatively similar evolution over time after seroconversion, also when stratified by rate of progression to AIDS. In the four years preceding AIDS diagnosis, a non-significant change in HIV RNA increase was seen, whereas a significant biphasic pattern was present for CD4 T-cell decline. CONCLUSION: HIV RNA level has more setpoint behaviour than CD4 T-cell count as far as the level shortly after seroconversion is concerned. However, with respect to the, clinically more relevant, marker evolution over time after seroconversion, a setpoint theory holds as much for CD4 T-cell count as for HIV RNA level.

Causal pathways of the effects of age and the CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles on AIDS development.

OBJECTIVE: To investigate the causal pathways by which age and the CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles influence progression to AIDS. DESIGN: Analysis of follow-up data from 2 cohort studies among homosexual men (n=400), having >10 years of follow-up. METHODS: The effects of the 4 cofactors on the CD4 and HIV-1 RNA trajectories after seroconversion were modeled in a random-effects model. A proportional hazards model was used to investigate their effect on the risk of AIDS after correction for CD4 cell count and RNA level. This approach allows investigation as to whether they influence AIDS progression by affecting CD4 count and RNA level or by other pathways. RESULTS: Persons of younger age or having the CCR2-64I or SDF-1 3'A mutation have significantly higher CD4 levels. Persons with the CCR5-Delta32 deletion or CCR2-64I mutation have significantly lower RNA levels. After correction for both CD4 count and RNA level, only the SDF-1 3'A mutation significantly increases the AIDS risk. CONCLUSIONS: Age and the CCR5-Delta32 deletion and CCR2-64I mutation influence AIDS progression by affecting CD4 and HIV-1 RNA. The SDF-1 3'A allele increases the AIDS risk, but this effect is countered by its effect on CD4 and HIV-1 RNA level.

Early levels of HIV-1 DNA in peripheral blood mononuclear cells are predictive of disease progression independently of HIV-1 RNA levels and CD4+ T cell counts.

BACKGROUND: The objective of this work was to assess the role of human immunodeficiency virus (HIV) reservoirs in the risk of disease progression, by studying the relationship between HIV DNA level in peripheral blood mononuclear cells (PBMCs) and progression toward acquired immunodeficiency syndrome (AIDS). METHODS: HIV-1 DNA levels in PBMCs were determined by quantitative polymerase chain reaction for 383 patients enrolled in the SEROCO Cohort Study who had experienced seroconversion and had been followed up for >8 years. We compared the predictive values of HIV DNA level, HIV RNA level, and CD4+ cell count. RESULTS: Between 6 and 24 months after seroconversion, HIV DNA level was a major predictor of progression to AIDS independently of HIV RNA level and CD4+ T cell count (adjusted relative risk [RR] for a 1-log(10) increase, 3.20 [95% confidence interval {CI}, 1.70-6.00]). HIV DNA level was also a major predictor of disease progression during the first 6 months after seroconversion (adjusted RR, 4.16 [95% CI, 1.70-10.21]), when HIV RNA level and CD4+ T cell count were less predictive. Thus, a combination of these 3 markers provides the best estimate of the risk of disease progression for each patient. CONCLUSIONS: Our results suggest that HIV DNA level could be a useful additional marker in clinical practice and could aid in helping to define the best time to initiate treatment for each patient.

Impact of 5 years of maximally successful highly active antiretroviral therapy on CD4 cell count and HIV-1 DNA level.

OBJECTIVES: To evaluate the impact on CD4 cell count and HIV-1 DNA level in peripheral blood mononuclear cells (PBMC) of long-term highly active antiretroviral therapy (HAART) in the setting of maximal success, i.e., constant plasma HIV-1 RNA load suppression. DESIGN: Retrospective analysis of patients selected for a constantly undetectable plasma HIV-1 RNA load since HAART initiation. METHODS: HIV-1 DNA was measured in PBMC using a real-time polymerase chain reaction assay. Loess estimates and regression analysis were used for modelling the variations of the CD4 cell count and HIV DNA level over time. RESULTS: The study included 41 patients chronically infected with HIV-1 who had been taking HAART for a median duration of 60.4 months and had an undetectable plasma HIV RNA load ever since the first 6 months of HAART; 25 were tested for HIV-1 DNA. The mean CD4 cell count increase was high during the first 18 months on therapy (168 x 10 cells/l per year), much lower afterwards (38 x 10 cells/l per year), independently of the baseline CD4 cell count. Most of the patients (73.2%) reached a CD4 cell count constantly > or = 400 x 10/l during follow-up. HIV-1 DNA showed a mean decrease of 0.48 log10 copies/10 PBMC during the first year, of 0.18 log10 copies/10 PBMC per year during the 2nd and 3rd years, but no significant decrease afterwards. CONCLUSIONS: These results question the benefit of very long-term maintenance of HAART in terms of CD4 gain and HIV-1 DNA reduction.

Increase in at-risk sexual behaviour among HIV-1-infected patients followed in the French PRIMO cohort.

OBJECTIVE: With the current increase in sexually transmitted infections in industrialized countries, we assessed the characteristics and plasma viral load of HIV-1-infected patients reporting sexual behaviour at risk for HIV transmission (SBR). DESIGN: The study population consisted of 223 patients with primary HIV-1 infection who were enrolled in the French PRIMO cohort between 1996 and 2001 and who had at least 3 months of follow-up. Patients were interviewed on condom use at each visit according to the partner (gender, steady versus casual nature, and HIV serostatus). SBR was defined as unprotected sex with partners of unknown or negative HIV serostatus. RESULTS: Sixty-one SBR were reported by 43 patients. SBR with casual partners increased from 5.1% in 1998 to 21.1% in 2001-2002, after a fall between 1997 and 1998. Reporting of SBR was more frequent among patients with casual partners, those with asymptomatic or briefly (< or = 15 days) symptomatic primary infection, and those who had developed clinical lipodystrophy or signs of anxiety/depression. Eighty-six per cent of patients reporting SBR had previously initiated highly active antiretroviral therapy (HAART); plasma viral load was above the detection limit (200/500 copies/ml) in 41% of visits reporting an SBR. Viral load was similar in patients reporting SBR and other patients, suggesting that the patient's knowledge of his/her response to HAART was not a major determinant of subsequent SBR. CONCLUSION: Our results confirm the recent increase in unsafe sex observed among HIV-infected individuals in industrialized countries. Levels of viral load of these individuals raise concern about the potential for re-emerging HIV epidemics.