Cellular immune responses to filarial
antigens were examined in persons before and 1 year after beginning treatment with
diethylcarbamazine (DEC). The subjects (17 microfilaremics, 13 asymptomatic amicrofilaremics, and 13 with
elephantiasis) had not responded to Brgia malayi adult worm
antigen (BmA) before
chemotherapy. T cell proliferative responses to BmA improved significantly after
therapy in the 3 clinical groups (P < .05) but was highest in the
elephantiasis patients and asymptomatic amicrofilareimics.
Cytokine release profiles after stimulation with parasite
antigen were analyzed. Production of
interferon (IFN)-gamma by BmA-stimulated mononuclear cells increased significantly after DEC treatment (geometric mean, 39.6-55.7 U/mL; P < .05), largely due to improved responses in
elephantiasis patients and asymptomatic amicrofilaremics. In contrast, BmA-induced
interleukin (IL)-4 release did not change significantly in these same patients
after treatment. Thus, both microfilaremic and amicrofilaremic
infections with B. malayi are associated with similar down-regulation of proliferative T cell function and IFN-gamma release.