Immunohistopathologic Study of Localized Plasma Proteins and Fixation of Guinea Pig Complement in Renal Lesions of Diabetic Glomerulosclerosis

Results of immunohistopathologic study of kidneys from six patients with diabetic glomerulosclerosis are presented and discussed. The data indicate that γ-globulin localized in hypereosinophilic glomerular exudates, hyaline arterioles, and coarsely fibrillar non-“cannon ball” type glomerular nodules may represent antibody-globulin in immune complexes on the basis of avidity for heterologous complement. Gamma globulin localized diffusely in a delicate “membranous” pattern in glomerular capillary walls, in “cannon ball” type nodules, in globlets within tubular epithelial cells, and in tubular casts does not fix heterologous complement and therefore is physicochemically or immunochemically different from the immunoglobulin in the latter sites. Evidence has also been presented which indicates that precipitation of fibrin in glomerular capillary walls, possibly in certain instances at sites of localized antigen-antibody complexes, and in glomerular capsules may play a significant role in the development of certain glomerular nodules and of thickened glomerular capsules. The identification and possible significance of tissue-bound insulin is also discussed.