Immunologic and virologic response to highly active antiretroviral therapy in the Multicenter AIDS Cohort Study.

OBJECTIVES: To evaluate prior antiretroviral therapy experience and host characteristics as determinants of immunologic and virologic response to highly active antiretroviral therapy (HAART). METHODS: We studied 397 men from the Multicenter AIDS Cohort Study (MACS) who initiated HAART between October 1995 and March 1999. CD4 cell count and HIV-1 RNA responses to HAART were measured at the first visit following HAART (short-term) and extending from the first visit to approximately 33 months after HAART (long-term). Prior antiretroviral experience was classified into three groups based on antiretroviral therapy use during the 5 years prior to HAART. Age, race and host genetic characteristics also were assessed for their effects on treatment response. RESULTS: Better short- and long-term CD4 cell and HIV-1 RNA responses were observed in the treatment-naive users. Intermittently and consistently experienced users did not significantly differ in response. Whereas race did not independently affect response, among those initiating HAART with > 400 x 10(6) CD4 cells/l, younger age and the Delta32 CCR5 genotype were associated with a better short-term CD4 cell response. There was a suggestion that having the protective CCR5 genotype also was associated with a better long-term CD4 cell response. CONCLUSION: Immunologic and virologic response to HAART was stronger in individuals who had no prior experience with the antiretroviral therapy agents subsequently included in their initial HAART regimen. Age, level of immune competence and immunogenetics appeared to play a role in the subsequent immune reconstitution following use of highly effective HIV therapy.

Natural history of human immunodeficiency virus type 1 viremia after seroconversion and proximal to AIDS in a large cohort of homosexual men. Multicenter AIDS Cohort Study.

The natural history of human immunodeficiency virus type 1 (HIV-1) viremia and its association with clinical outcomes after seroconversion was characterized in a cohort of homosexual men. HIV-1 RNA was measured by reverse-transcription polymerase chain reaction (RT-PCR) in stored longitudinal plasma samples from 269 seroconverters. Subjects were generally antiretroviral drug naive for the first 3 years after seroconversion. The decline in CD4 lymphocyte counts was strongly associated with initial HIV RNA measurements. Both initial HIV RNA levels and slopes were associated with AIDS-free times. Median slopes were +0.18, +0.09, and -0.01 log10 copies/mL, respectively, for subjects developing AIDS <3, 3-7, and>7 years after seroconversion. In contrast, HIV RNA slopes in the 3 years preceding AIDS and HIV RNA levels at AIDS diagnosis showed little variation according to total AIDS-free time. HIV RNA load at the first HIV-seropositive visit ( approximately 3 months after seroconversion) was highly predictive of AIDS, and subsequent HIV RNA measurements showed even better prognostic discrimination.

Impact of potent antiretroviral therapy on the incidence of Kaposi's sarcoma and non-Hodgkin's lymphomas among HIV-1-infected individuals. Multicenter AIDS Cohort Study.

Effective HIV-1 therapies may directly or indirectly impact the development of AIDS-associated malignancies. Using data from the Multicenter AIDS Cohort Study, a longitudinal cohort study of the natural history of HIV-1 infection among homosexual men, the incidence rates of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma (NHL) over calendar time were determined for the 1813 HIV-1-seropositive men enrolled in 1984 through 1985. Poisson regression models were used to identify statistically significant temporal trends. Nested case control studies were used to assess whether recent cases of these malignancies represented treatment breakthroughs. The incidence of KS as a presenting AIDS illness significantly (p = .003) declined from 25.6 cases per 1000 person-years (95% confidence interval [CI], 21.8-29.9) in the early 1990s to an average incidence of 7.5 per 1000 person-years (95% CI, 3.4-16.7) in 1996 through 1997. In contrast, the incidence of NHL has continued to increase significantly (p < .001) at a rate of 21% per year since 1985, although a possible recent decrease is suggested. None of the recent KS cases and only 1 of 8 NHL cases had used the potent antiretroviral therapies, compared with >70 percent of the HIV-1-seropositive men who were free of malignancies and observed over the same time period. These results may be due to an indirect protection against developing KS by the boosting of the immune system by antiretroviral therapies. However, it is important to clarify the direct therapeutic effect on the pathogenic disease mechanism of human herpesvirus type 8 (HHV-8), the agent postulated to be important in the causal pathway of KS. The absence of a similar effect on NHL may be due to a lack of effect on its pathogenesis or because potent antiretroviral therapies need to be administered early in the disease process and the cases that have occurred represent outcomes following a long latency period. With additional follow-up, an impact on NHL may yet be observed.