Eosinophil sequestration and activation are associated with the onset and severity of systemic adverse reactions following the treatment of onchocerciasis with ivermectin.

Author(s): Cooper PJ, Awadzi K, Ottesen EA, Remick D, Nutman TB

Affiliation(s): Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, MD 20892-0425, USA. pcooper@atlas.niaid.nih.gov

Publication date & source: 1999-03, J Infect Dis., 179(3):738-42.

Publication type: Clinical Trial; Randomized Controlled Trial

To investigate the role of eosinophil activation and sequestration in the development and severity of adverse reactions after the treatment of Onchocerca volvulus infection, 40 O. volvulus-infected Ghanaians were randomized to receive placebo or standard- or high-dose ivermectin. Subjects were examined for typical physiologic and clinical events before and up to 48 h after treatment. Plasma samples were tested for interleukin (IL)-5 and eosinophil degranulation products (e.g., eosinophil-derived neurotoxin, EDN). After treatment, peripheral eosinophil counts declined in ivermectin-treated groups (P<.001), whereas circulating levels of IL-5 (P<.01) and EDN (P<.05) increased. Cumulative levels of IL-5 and EDN correlated with reaction scores (P<.01). High-dose ivermectin was associated with more-severe reactions, more-profound eosinopenia, and higher circulating levels of IL-5 and EDN, compared with the standard dose. These results suggest that eosinophil sequestration and activation/degranulation are associated with the initiation and severity of ivermectin-associated adverse reactions.