Abnormal binding of negatively charged serum proteins to diabetic basement membranes is largely a systemic phenomenon

Direct immunofluorescence employing goat anti-human IgG, IgA, IgM, C3 component of complement, fibrinogen, albumin, and polyvalent immunoglobulins was performed on postmortem samples of gingiva, parotid gland, thyroid, kidney, and pancreas tissue of 15 diabetic and 15 control patients.