IgA nephropathy with complement deficiency

We treated a female patient suffering from immunoglobulin A (IgA) nephropat hy and congenital deficiency of the ninth component of the complement syste m (C9). She was admitted with hematuria and proteinuria, and the C9 deficie ncy was diagnosed based on the low hemolytic activity of 50% of the hemolyt ic unit of the complements (CH50) and the normal C3 level in the plasma, Re nal biopsy revealed mild mesangial proliferation, and immunofluorescence ex amination revealed mild mesangial deposits of IgA and C3 with the same dist ribution. We discuss the pathogenesis of IgA nephropathy and the role of th e complements in its progression.