Complement activation has a role in the pathogenesis of IgA nephropathy, an autoimmune
disease mediated by pathogenic immune complexes consisting of galactose-deficient IgA1
bound by antiglycan antibodies. Of three complement-activation pathways, the alternative
and lectin pathways are involved in IgA nephropathy. IgA1 can activate both pathways in
vitro, and pathway components are present in the mesangial immunodeposits, including
properdin and factor H in the alternative pathway and mannan-binding lectin, mannan …