Effect of chloroquine on human immunodeficiency virus (HIV) vertical transmission

Over 2 million children globally are HIV positive. More than 90% are infected in utero from their mothers. Current pharmacological methods to reduce the rate of vertical transmission are too expensive for the developing world. Chloroquine, a cheap, widely available drug, has anti-HIV properties. We conducted a pilot study to determine if chloroquine can reduce HIV vertical transmission.

287 samples of stored, frozen cord blood from a cohort of Ugandan infants born to HIV positive mothers were analyzed for concentrations of chloroquine and its two major metabolites, monodesethylchloroquine and didesethylchloroquine. The HIV status of each infant was determined by ELISA with Western Blot confirmation at 15 and 18 months of age.

49% of samples had measurable chloroquine or metabolite. Of those with measurable drug, the higher concentrations of chloroquine and its metabolites were more frequently associated with HIV negative infants. However, only the median concentration of didesethylochloroquine was significantly higher in HIV negative infants vs. HIV positive infants (1.6 ng/ml vs. 0.9 ng/ml, p=0.05).

Nearly half of all infants in a Ugandan cohort are exposed to chloroquine in the last trimester of pregnancy. Such random maternal chloroquine use may be associated with a decreased rate of HIV vertical transmission. The issue of maternal chloroquine use requires controlled study before any clinical conclusions may be drawn.