Detection of immunoglobulins and other serum proteins in the dermal and glomerular capillary walls from patients with diabetes mellitus.

Deposition of immunoglobulins or acute phase reactant (APR) proteins in the dermal and glomerular capillary walls from patients with diabetes mellitus was examined to determine whether development of microangiopathy in such patients was related to exudation and/or entrapment of these proteins. Skin and renal biopsy specimens were obtained from patients with diabetic nephropathy and diabetes mellitus without nephropathy. These biopsy samples were stained with FITC-labeled anti-human IgG, IgA, IgM, C3, APR proteins, and beta-lipoprotein antisera. Linear depositions of IgA, IgG, and/or APR proteins were observed in the dermal and/or glomerular capillary walls from some patients with diabetic nephropathy or diabetes mellitus without nephropathy. It is indicated that deposition of such immunoglobulins in the dermal and glomerular capillary walls might be due to exudation and/or entrapment of these substances in patients with diabetes mellitus.