A possible common pathogenesis of the mesangial IgA glomerulonephritis in patients with Berger's disease and Schönlein-Henoch syndrome.

High serum levels of polymeric IgA, partially as immune complexes, have been found in patients with Berger's disease and Schönlein-Henoch syndrome. Polymeric IgA was also found in the renal mesangium in both entities as judged by its affinity for the human secretory component. These data reinforce the clinical and morphological suspicion that both entities may represent variations of the spectrum of the same disease.