DEPRESSION OF ANTIGEN-SPECIFIC INTERLEUKIN-5 AND INTERFERON-GAMMA RESPONSES IN HUMAN LYMPHATIC FILARIASIS AS A FUNCTION OF CLINICAL STATUS AND AGE

In an area in which brugian filariasis is endemic, when cytokine level s were analyzed as a function of clinical status comparing those who w ere asymptomatic and amicrofilaremic with those who were microfilaremi c, it was found that both interferon (IFN)-gamma and interleukin (IL)- 5 were suppressed in microfilariae carriers (P < .01 and P < .001, res pectively), but IL-4 was unabated. Age had a significant effect on cyt okine production in both groups. In asymptomatic amicrofilaremic subje cts, IL-4 production was high in young persons and decreased with age, whereas in microfilaremic subjects, IL-4 increased significantly with age. Conversely, IFN-gamma showed a tendency to increase with age in asymptomatic amicrofilaremic subjects but not in microfilaremic subjec ts, IL-5 decreased significantly with increasing age in both asymptoma tic amicrofilaremic and microfilaremic groups, These results indicate that the length of exposure to and infection with filarial parasites c an each exert a substantial effect on the cytokine response profiles o f host T cell populations.