Slow progression of HIV-1 infection in a cohort of antiretroviral naïve hotel workers in Dar es Salaam, Tanzania as defined by their CD4 cell slopes.

Data on slow progression following HIV-1 infection in Africa are sparse. From a study on the natural history of HIV-1 infection in Dar es Salaam, Tanzania, an analysis of immunological and clinical data from 237 HIV-1 seropositive individuals was performed. Annual CD4 cell determinations were carried out by flow cytometry. None was on antiretroviral treatment. CD4+ cell slopes were obtained by fitting a linear regression model. A study population of 50 individuals with >3 CD4 cell determinations and followed for >5 y had a mean follow-up of 72.7 months, and mean 5.7 CD4+ cell determinations. With a criterion of maintaining a CD4 cell count >or=500 cells/ml, 8 of the 50 (16.0%) were long-term non-progressors (LTNP). With a definition of maintaining a CD4+ cell slope <or=-10 (a loss of 10 or less cells per y), 13 (26.0%) were long-term slow progressors (LTSP). 11 of them (84.6%) had a baseline CD4 cell count <500 cells/microl and 5(38.5%) had a baseline CD4 cell count less than 350 cells/microl. An analysis of the selection bias introduced during slope determination is presented. With no selection, 24 (23.3%) would have documented slow CD4 progression among those enrolled for 5 or more y regardless of CD4 determinations.