PTX3 and lupus nephritis: As serum PTX3 levels was closely associated with disease activity and severity of lupus nephritis in previous studies,16,18,27 and PTX3 deposition and renal fibrosis were significantly lower in anti-PTX3 auto-antibodies positive patients compared with those negative, confirmed by experimental animal model,17–19 we speculated that anti-PTX3 auto-antibodies and PTX3 might exert opposite effect under pathological conditions.