Unresponsiveness of lymphocytes in patent filarial infection: modulation by diethylcarbamazine.

The lymphocytes of lymph nodes and spleen of Mastomys natalensis infected with Litomosoides carinii were unresponsive to specific filarial antigens during patent stage of the infection. The effect of diethylcarbamazine (DEC) on these responses has been investigated. DEC administered orally at 150 mg/day for 5 days to the animals reduced markedly the circulating levels of microfilariae. At this stage the lymphocyte proliferative responses improved to specific microfilarial antigens. On follow-up a month later when the DEC effect waned and microfilaremia again sets in, both the lymph node and the spleen cells became unresponsive to specific microfilarial antigens. These findings indicate that decrease in circulating parasites on treatment with DEC could restore the cellular responsiveness to parasite antigens.