Malaria Treatment Efficacy among People Living with HIV: The Role of Host and Parasite Factors

Identification of an effect of HIV-associated immunosuppression on response to antimalarial therapy would help guide management of malaria infection in areas of high HIV prevalence. Therefore, we conducted an observational study of people living with HIV infection in Blantyre, Malawi. Participants who developed malaria were treated with sulfadoxine-pyrimethamine (SP) and followed for 28 days. Molecular markers for SP resistance were measured. One hundred seventy-eight episodes of malaria were assessed. The 28-day cumulative treatment failure rate was 29.1%. In univariate analysis, CD4 cell count was not associated with treatment failure (hazard ratio 0.6, 95% confidence interval 0.3-1.2). Among children, the risk of treatment failure increased with infection with SP-resistant parasites and anemia. Decreased CD4 cell count was not associated with impaired response to antimalarial therapy or diminished ability to clear SP-resistant parasites, suggesting that acquired immunity to malaria is retained in the face of HIV-associated immunosuppression. sites are resistant. We hypothesized that if HIV-associated immunosuppression interferes with malaria immunity, then lower CD4 cell counts would be associated with an impaired ability of SP treatment to cure infections with SP-resistant parasites. To identify both host and parasite factors that contribute to antimalarial drug efficacy, we studied HIV-infected adults and children enrolled in a longitudinal study in Blantyre, Malawi. When participants developed symptomatic malaria, they were treated with SP, according the Malawi national policy, and were followed for 28 days to assess the efficacy of the drug. Molecular analyses of infecting parasites were car- ried out to identify the presence of genetic mutations associ- ated with resistance to SP.