Eotaxin expression in Onchocerca volvulus-induced dermatitis after topical application of diethylcarbamazine

In persons with onchocerciasis, topical application of the anthelminthic diethylcarbamazine (DEC) induces clinical and histologic responses similar to acute papular onchodermatitis, including recruitment of eosinophils to the skin. To determine whether the eosinophil chemokine eotaxin is likely to be associated with eosinophil recruitment in onchodermatitis, DEC was applied to a 5-cm2 area on the skin of infected persons, and biopsies were taken from lesions 24 h later. Histologic analysis showed elevated dermal and epidermal eosinophils compared with tissue from an adjacent (untreated) site. Reverse transcription-polymerase chain reaction showed that eotaxin gene expression in DEC-treated skin was elevated 2- to 17-fold compared with control tissue. Eotaxin immunoreactivity was noted in mononuclear cells and eosinophils in the perivascular region of the dermis and in lymphatic and vascular endothelial cells. Together, these observations are consistent with a role for eotaxin in recruitment of eosinophils to the dermis in early stage onchocercal skin disease.