Immunopathological analysis of acute phase reactant (APR) proteins in glomeruli from patients with diabetic nephropathy.

The levels of immunoglobulins, complement components and APR proteins including alpha 1-antitrypsin (alpha 1-AT), alpha 1-acid glycoprotein (alpha 1-AG), alpha 2-macroglobulin (alpha 2-MG) and haptoglobin (Hpt) in the sera, as well as glycosylated or nonglycosylated protein fractions of these proteins in the sera, were examined by laser nephelometry in 49 patients with diabetes mellitus. Immunofluorescence studies of immunoglobulins, beta-lipoprotein (beta-Lp), complement components and APR proteins in the kidney and skin tissues of patients with diabetic nephropathy were performed to elucidate whether such factors might play a role in the development of the vascular changes in this disease. The levels of alpha 1-AT and alpha 2-MG in the sera as well as glycosylated or nonglycosylated protein fractions of these proteins in the sera from patients with diabetic nephropathy, were significantly greater than those in healthy adults. Marked linear deposition of these proteins in the glomerular or dermal vascular walls was observed in the same patients. In particular, IgG and alpha 1-AT were accumulated in the glomeruli of patients with the nodular type of this disease. The intensity of alpha 1-AT or IgG deposition in glomerular capillary walls treated with a high concentration (4 mol) of NaCl was markedly decreased in such patients. It appeared that serum APR proteins with or without glycosylation underwent exudation into the glomerular and dermal vascular walls, and then accumulated in these walls in patients with diabetic nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)