IgA-IgG nephropathy: a clinicopathologic entity with slow evolution and favorable prognosis.

Renal biopsy specimens were obtained from nine patients with proteinuria and persistent macroscopic or microscopic hematuria. Histologic examination either disclosed no abnormality or showed moderate mesangial thickening and occasionally, evidence of focal segmental glomerulonephritis. Immunofluorescent studies revealed diffuse generalized mesangial deposits of IgA, IgG and betalc in all specimens. Fibrinogen deposits were present in the mesangial space in four specimens only, while IgM was uniformly absent. Serial sections of identical glomeruli allowed the localization of betalc within both IgA and IgG deposits. Ultrastructural studies of the renal biopsy specimens showed accumulation of electron-dense material in the subendothelial region of the capillary loops and the mesangium, with thickening of its matrix. Follow-up data indicated a generally good prognosis.