Idiopathic linear glomerular IgA deposition.

Linear deposition of IgA immunoglobulin was found along the glomerular basement membrane in two patients with normal renal function and no pulmonary abnormalities. One patient had recurrent gross hematuria and a mild focal proliferative glomerulonephritis without deposits on electron microscopy; the second patient had a renal cell carcinoma. This observation of linear IgA antibody deposition in the absence of Goodpasture's syndrome or diabetes mellitus extends the spectrum of diseases associated with glomerular basement membrane-IgA deposition.