RANTES in onchocerciasis: changes with ivermectin treatment

Adverse reactions are seen relatively frequently after treatment of onchocerciasis patients with ivermectin. The chemokines RANTES and IL-8, which have both chemotactic and activation properties for eosinophils and neutrophils, respectively, may have a role in the pathogenesis of post-treatment reactions. Circulating levels of the chemokines and the cytokines tumour necrosis factor-alpha (TNF-alpha) and IL-6 were measured in the plasma of 22 Onchocerca volvulus-infected subjects. Peaks of mean circulating levels of RANTES and TNF-alpha were seen at 6 h after ivermectin administration. Peripheral eosinophil counts declined at 36 h post-treatment and an early peak in RANTES levels was associated with a delay in peripheral eosinopenia. RANTES levels were negatively correlated with severity of rash (P < 0.001) and lymphoedema (P < 0.05), suggesting that high circulating levels of RANTES may inhibit eosinophil sequestration. No changes in circulating levels of IL-8 were seen. These findings suggest a possible role of circulating RANTES in modulating eosinophil sequestration in vivo.