Novel roles of complement in systemic lupus erythematosus - Hypothesis fora pathogenetic vicious circle

We propose that impaired complement function enhances a pathogenetic viciou s circle in SLE. In this process, induction and clearance of apoptotic cell s is central. Apoptosis could be triggered by various etiological factors, such as infection, UV light, and drug reactions. Clearance of apoptotic mat erial is reduced when complement function is impaired. Apoptosis leads to i ncreased exposure of nuclear antigens to the immune system, to which estrog enic hormones could contribute. This could in turn lead to activation of au toreactive B cells, autoantibody production, and immune complex formation, all of which is accelerated by hypocomplementemia. Immune complexes may, at least partly via complement dependent mechanisms, accelerate apoptosis.