The primary complement components contained in circulating immune complexes in oligoarticular and polyarticular juvenile idiopathic arthritis patient sera are C1q and C4: evidence of classical complement activation

Purpose Circulating immune complexes (CICs) from juvenile idiopathic arthritis (JIA) sera have been shown to contain bound complement components; however, whether the classical or alternative pathway is the main pathway involved remains undetermined. To delineate the role of these pathways in the disease process, we measured activated complement products bound to CICs in sera from 100 JIA patients.