Ocular and systemic complications of diethylcarbamazine therapy for onchocerciasis: Association with circulating immune complexes

Diethylcarbamazine (DEC) therapy for Onchocerca volvulus infection results in frequent ocular and systemic complications, but the pathogenesis of these complications is unclear. Twenty men with O. volvulus infection were treated over a period of six months with DEC given daily for one week and weekly thereafter. Major systemic and ocular complications included proteinuria, severe pruritis, visual field constriction, optic nerve pallor, chorioretinitis, anterior uveitis, and punctate keratitis. Level of circulating immune complexes (CICs) were increased (>11% [¹²⁵I]C1q binding) in 14 of the 20 men prior to treatment. Persons with pretreatment C1q binding activity of >30% were at increased risk to develop constriction of visual fields (P < 0.05) and proteinuria (P < 0.015). Linear regression analysis revealed a striking correlation between pretreatment levels of CICs and the total number of both systemic and ocular complications (P < 0.001) and ocular complications alone (P < 0.005). These results suggest that CICs may be important in the pathogenesis of the delayed systemic and ocular complications following DEC therapy for O. volvulus infection.