Original Article Complement in ANCA-associated glomerulonephritis

Background. Anti-neutrophil cytoplasmic antibodies (ANCA) are found in pauci-immune necrotizing crescentic glomerulo-nephritis. In the past, the role of complement in ANCA-associated vasculitis (AAV) was assumed to be minimal. More recently, however, it was found that blocking the comple-ment cascade in a mouse model of AAV reduces glomerular damage. Immune complex deposits have been found in biopsies from AAV patients. In this study, we questioned whether im-mune complex formation or deposition may result in comple-ment activation in ANCA-associated glomerulonephritis. Methods. ANCA-positive patients from the Limburg Renal Registry were included between 1979 and 2011. Renal histology was documented together with immunoglobulin and comple-ment immunofluorescence. In addition, C3d, properdin, C4