Serum secretory IgA and IgM and free secretory component in IgA nephropathy.

IgA nephropathy (IgAN) is characterized by the presence of IgA and C3 deposits in the mesangium. Mesangial IgA is mostly dimeric IgA1 with a J chain, lacking a secretory component. In view of the recent demonstration of elevated serum levels of secretory component and secretory IgA in liver disease and HIV infection associated with hyper-IgA, we measured… (More)