XI International Conference on AIDS
Vancouver, BC, July 7 - 12, 1996

Mo.B.1260

Correlates of Long-Term Survival and Immunologic Nonprogression Among HIV-1 Infected Sex Workers in Nairobi

Background & Objectives

Much interest has recently been focused on the characterization of disease progression among HIV-1 infected individuals. The average time from infection to death is 10 years, and most long-term survivors have immunologic evidence of disease progression. Since 1985 we have studied the immuno-epidemiology of HIV-1 in a cohort of sex-workers in Nairobi, Kenya. The time from HIV-1 infection to development of AIDS in this cohort is extremely short, a median time to AIDS of 4.0 years. The aim of this study was to characterize factors associated with long-term survival and long-term immunologic nonprogression among these women.

Methods

Women were followed using a standardized questionnaire, physical exam, cervical swabs, and blood work (HIV-1 serology, CD4 counts, PBLs and RPR) at six monthly intervals. Blood was also obtained for MHC class I/II typing. Long-term survivors (LTS) were defined as those followed 7 years after initial HIV-1 diagnosis, with CD4 counts <500/mm3. Immunologic nonprogressors (LTNP) were those surviving 7 years, who maintained a normal CD4 count. Rapid immunologic progressors (RP) were those with CD4 count <200/mm3 within 2 years of seroconversion. 567 sex workers seen in follow-up in 1995, who did not meet any of the three definitions, were defined as normal progressors.

Results

118 women were identified as LTS, 30 as LTNP, and 50 as RP. LTNP were younger than RP at seroconversion (P<0.005), and had a shorter duration of prostitution (P<0.05). There was a trend to higher risk sexual behaviours in the LTNP group, including a higher number of sexual partners (P=0.06), less condom use (P=0.07), and increased frequency of gonorrhoea (P=0.08). Compared to LTS, LTNP had a trend to shorter duration of prostitution at first HIV-1 positive visit (P=0.09), but were otherwise similar. LTNP was associated with MHC alleles A34 (P<.05); and inversely associated with A23 (P<0.01), B65 (P<0.02), and B45 (P=0.06).

Conclusions

Nonprogressors appear be younger and engage in more high-risk sexual behaviours. Associations with MHC Class I alleles suggest that more effective immune responses may be responsible for LTNP.

• Dr. Joshua Kimani
  Department of Medical Microbiology
  University of Nairobi,
  P.O. Box 19676, Nairobi
  Kenya, East Africa