Mesangial IgA in IgA nephropathy arises from the mucosa.

Numerous studies have attempted to elucidate the pathogenetic mechanisms of IgA nephropathy, analyzing kidney, serum, lymphocytes, and lymphoid tissue of patients with this glomerulonephritis. Based on studies of the molecular characteristics of the mesangial IgA, clinical features, and immunologic analysis of the mucosal tissue, a wide array of findings suggest that mesangial IgA indeed arises from the mucosa. These three areas of research are discussed, as well as the hypothesis of a systemic origin for the mesangial IgA.