INTERLEUKIN-6 AND TUMOR-NECROSIS-FACTOR IN THE PATHOGENESIS OF ADVERSE REACTIONS AFTER TREATMENT OF LYMPHATIC FILARIASIS AND ONCHOCERCIASIS

Adverse reactions following treatment of onchocerciasis and bancroftia n filariasis are common and frequently severe. They are generally caus ed not by direct drug toxicity but by host inflammatory responses to d ying microfilariae. To define the responsible mechanism, serial blood levels of interleukin-6 (IL-6) and tumor necrosis factor (TNF) were st udied in 15 microfilaria-positive patients (10 with bancroftian filari asis, 5 with onchocerciasis) and 4 microfilaria-negative persons after diethylcarbamazine treatment. Elevations in IL-6 correlated with the occurrence and severity of clinical symptoms after treatment; for the onchocerciasis patients IL-6 levels directly reflected pretreatment in tensity of infection. Serum TNF levels also rose but did not correlate directly with infection intensity or reaction severity. Microfilaria- negative controls remained asymptomatic with no significant rise in ei ther cytokine. These findings suggest an etiologic role for systemical ly elevated cytokines in the inflammatory reactions developing after t reatment of filarial infections in humans.