INCREASED SERUM LEVELS OF IGA ANTIBODIES TO HSP70 PROTEIN IN PATIENTSWITH DIABETES-MELLITUS - THEIR RELATIONSHIP WITH VASCULAR COMPLICATIONS

We measured class-specific antibodies to the mycobacterial hsp70 prote in in 67 patients with diabetes mellitus (27 type 1 and 40 type 2) wit h or without vascular complications. Using ELISA, the levels of IgG an d IgM antibodies in the sera of diabetic patients did not significantl y differ either from those of healthy control subjects or between both types of diabetes, regardless of gender, disease duration, HbA1 level , or type of vascular complication. In patients with type 2 diabetes, the mean serum IgA levels were significantly higher than those in thei r matched controls [274(71) mg/dl vs 208(88) mg/dl; P < 0.01. In this group of patients, the IgA antibody titer was significantly correlated to the serum IgA level (r = 0.334; P < 0.01). Serological autoimmunit y (IgG or IgM type) to hsp70 protein is common in both the normal and the diabetic population. The increased IgA levels and anti-hsp70) IgA titers in the sera of diabetics suggest a possible role of IgA in the pathogenesis of the vascular complications of diabetes mellitus. (C) 1 996 Academic Press, Inc.