Tissandié and colleagues report in this issue on their studies of IgA1 glycosylation and biological activities of IgA1-containing circulating immune complexes in patients with alcoholic cirrhosis who developed secondary renal disease with IgA deposits, secondary IgA nephropathy. Their seminal findings demonstrate abnormal glycosylation of IgA1 N-linked as well as O-linked glycans. Furthermore, their work reveals unique biological properties of immune complexes in these patients as compared with those in patients with primary IgA nephropathy. © 2011 International Society of Nephrology.