Heightened measures of immune complex and complement function and immune complex-mediated granulocyte activation in human lymphatic filariasis.

The presence of circulating immune complexes (CICs) is a characteristic feature of human lymphatic filariasis. However, the role of CICs in modulating granulocyte function and complement functional activity in filarial infection is unknown. The levels of CICs in association with complement activation in clinically asymptomatic, filarial-infected patients (INF); filarial-infected patients with overt lymphatic pathologic changes (CPDT); and uninfected controls (EN) were examined. Significantly increased levels of CICs and enhanced functional efficiency of the classical and mannose-binding lectin pathways of the complement system was observed in INF compared with CPDT and EN. Polyethylene glycol-precipitated CICs from INF and CPDT induced significantly increased granulocyte activation compared with those from EN, determined by the increased production of neutrophil granular proteins and a variety of pro-inflammatory cytokines. Thus, CIC-mediated enhanced granulocyte activation and modulation of complement function are important features of filarial infection and disease.