Eosinophilia and elevated serum levels of eosinophil major basic protein and Charcot-Leyden crystal protein (lysophospholipase) after treatment of patients with Bancroft's filariasis.

Abstract

Eosinophilia is a common sequela of treatment in patients infected with the parasitic helminth Wuchereria bancrofti. The relationship between peripheral blood eosinophil levels and serum levels of eosinophil granule major basic protein (MBP) and Charcot-Leyden crystal (CLC) protein was investigated in 37 patients with bancroftian filariasis who were treated with diethylcarbamazine (DEC). Before treatment with DEC, eosinophil levels and serum levels of CLC protein, but not MBP, were significantly elevated in both filariasis patients and an uninfected endemic control population. After treatment, patients with microfilaremia developed an initial eosinopenia followed by significant increases in their eosinophil levels and serum levels of both MBP and CLC protein, which peaked 1-2 wk after initiating treatment. Before treatment, eosinophil levels and serum levels of MBP and CLC protein were unrelated to the number of microfilariae in circulation, but after treatment, the degree of eosinophilia and the elevations in serum MBP and CLC protein were significantly correlated with the patients'' microfilarial worm burdens before treatment. In microfilaremic patients on DEC therapy, there was a statistically significant increase in serum MBP levels concomitant with the initial decrease in eosinophil levels observed on day 1 of therapy in these patients. Patients with filariasis (elephantiasis, hydroceles or filarial fevers) but without microfilaremia and an uninfected endemic control population showed no change in their eosinophil levels or serum MBP or CLC protein levels during an identical course of DEC therapy. The eosinophilic response resulting from DEC therapy of patients with microfilaremia allows for the study of the relationship between eosinophilia, eosinophil function and possibly eosinophilopoiesis as reflected by the synthesis and/or release of eosinophil proteins in humans exposed to a quantifiable antigenic stimulus.