Nephrotic syndrome associated with Fanconi Syndrome. Immunopathogenic studies of tubulointerstitial nephritis with autologous immune-complex glomerulonephritis.

The nature of renal lesions in a patient with simultaneous onset of the Fanconi syndrome and nephrotic syndrome was investigated by immunologic studies of the patient's serum, cryoproteins, and renal tissue. Acute severe tubulointerstitial nephritis and generalized segmental glomerulonephritis were present. Renal tubular epithelial (RTE) antigen, IgG, and Clq were localized in the glomerull and proximal tubules. Cryoprecipitates containing RTE antigen and anti-RTE antigen were isolated from the patient's serum antibody to RTE antigen was detected in the serum of the patient. However, antibody to tubular basement membrane was not found in the cryoproteins or serum. The unusual simultaneous presentation of these two syndromes in our patient possibly represents a common etiology: tubular damage with release of RTE antigen and subsequent development of immune-complex glomerulonephritis mediated by renal tubular epithelial antigen and antibody to this antigen.