Tumor directed antibody and carcinoembryonic antigen in the glomeruli of a patient with gastric carcinoma.

A patient dying of gastric carcinoma was one of a group of cancer patients examined for the presence of glomerular immune complex deposits not associated with the nephrotic syndrome. The deposits were distributed in the mesangial and subendothelial regions. This distribution is found in experimental animals with neoplasia and glomerulopathy as well as in over 30 per cent of humans with cancer. Immunofluorescence showed IgG and C3 in the patient's glomeruli. Carcinoembryonic antigen was identified in the patient's glomeruli by the immunoperoxidase staining method. An IgG antibody was eluted from the kidney and found to be reactive with the patient's tumor, as well as another patient's colonic carcinoma. This reactivity was blocked by preincubation of the tumor substrate with anticarcinoembryonic antigen. Thus, both a tumor associated antigen and a corresponding antibody were shown to be contained in the glomerular deposits. It is concluded that circulating immune complexes of high molecular weight containing carcinoembryonic antigen produced by the gastric carcinoma led to the formation of subendothelial deposits without significant renal damage. This is in contrast to the usual finding of membranous glomerulonephritis among cancer patient with the nephrotic syndrome and more closely resembles the animal models. Whereas tumor reactive antibodies can be found in the glomeruli of patients with cancer, a specific tumor associated antigen to which the antibody is reactive has only occasionally been demonstrated.