Bancroftian filariasis: profile of serum antifilarial antibody and circulating parasite antigen.

Forty-five serum specimens collected from persons living in a filaria-endemic community in Maili Nane, Coastal Kenya were analyzed by ELISA for levels of isotype specific antifilarial antibody and by Og4C3 ELISA for circulating parasite antigen. Mean levels of IgG1, IgG2, and IgG3 were lower in microfilaraemic persons than in amicrofilaraemic individuals. In contrast, mean levels of antifilarial IgG4 were significantly higher in microfilaraemic persons (p = 0.0374). Serum samples from all microfilaremic persons were positive for circulating antigen as were 15% of samples from amicrofilaremic and asymptomatic persons. The Og4C3 antigen assay may have value as a technique for identifying and targeting communities for control efforts.