Rate of decline of absolute number and percentage of CD4 T lymphocytes among HIV-1-infected adults in Dar es Salaam, Tanzania

OBJECTIVE: To determine the rate of decline of CD4 T lymphocytes among HIV-1-infected individuals. DESIGN AND SETTING: A prospective open cohort study of workers in three hotels in Dar es Salaam. METHODS: The workers were seen yearly during the study. CD4 T lymphocyte counts were determined using flow cytometry. The CD4 T-lymphocyte slopes were determined using a linear regression model. RESULTS: During the 9-year study period 682 subjects were selected for lymphocyte subset determinations. Of these, 94 HIV-1-seroprevalent (72%), 77 HIV-1-seroincident (67%) and 325 seronegative (75%) individuals had three or more CD4 T-cell determinations, and were used for calculations of CD4 cell slopes with a mean follow-up period of 71.4, 52.9 and 86.0 months, respectively. The median yearly decline of the CD4 T-lymphocyte counts and percentages among seroprevalent individuals was -21.5 cells/microl and -1.3%; among the seroincident individuals the median decline was -22.0 cells/microl and -1.5%. In seroincident individuals the mean duration to a CD4 T-lymphocyte level corresponding to a definition of AIDS was 13.3 years or 11.8 years for CD4 cell counts or percentages, respectively. HIV-1-seropositive subjects who died had significantly steeper CD4 cell slopes than those who survived. CONCLUSION: The rates of CD4 T-lymphocyte decline in HIV-1-infected individuals in our population are similar to those reported in Europe and north America.