ELEVATIONS IN GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND INTERLEUKIN-5 LEVELS PRECEDE POSTTREATMENT EOSINOPHILIA IN ONCHOCERCIASIS

The eosinophil survival assay was used to quantitate cytokines in 17 s erial serum samples from 10 patients treated for onchocerciasis with d iethylcarbamazine. Eosinophils isolated from normal donors were cultur ed for 4 days in the presence of patients' sera, and cell viability wa s determined, Serum specimens from 9 of 10 patients enhanced eosinophi l survival from 4.8% +/- 2.2% (mean +/- SE) before treatment to 50.0% +/- 6.4% after treatment, Survival enhancement activity peaked before posttreatment eosinophilia. Antibodies to interleukin (IL)-5, granuloc yte-macrophage colony-stimulating factor (GM-CSF), and IL-3 were used to block cytokine activity in 22 serum samples. Antibodies to IL-5 blo cked survival in 5 samples, antibodies to GM-CSF blocked survival in 6 samples, and a combination of antibodies to IL-5 and GM-CSF blocked s urvival in 8 additional samples, Overall, posttreatment sera from pati ents treated for onchocerciasis enhanced eosinophil survival; both GM- CSF and IL-5 may promote the posttreatment eosinophilia in filarial in fection.