Levels of various components of the classical and alternative pathways of complement activation in diabetes mellitus patients

: The state of the complement system was studied in 91 patients with insulin dependent and in 47 patients with non-insulin dependent diabetes. A study was made of the quantity of hemolytically effective molecules of some components C2, C4, C3, C5 of classic and factors B and D of alternative pathway of activation. Complement components were studied for control in 51 healthy blood donors. Antigens B8 and B18 of the HLA-histocompatibility system were studied in parallel in 24 patients and 21 donors. A significantly raised level of components C3 and C4, factors B and D was revealed in the patients with insulin dependent diabetes as compared to the controls (p less than 0.05). In non-insulin dependent diabetes C4, factors B and D were significantly raised and the level of C5 was lowered (p less than 0.05). In the patients with insulin dependent diabetes having antigens B18 the level of C3 was raised and the level of C4 was lowered as compared to the controls. The level of factors B and D was also lower than that in the diabetic patients. An analysis of the content of the complement components in 31 diabetic patients with diabetic nephropathy indicated a decrease in the levels of components C3 and C5 and an increase in the content of C4 (p less than 0.001) as compared to the normal. Diabetes was accompanied by considerable variations as compared to normal values characterizing the state of the complement system and reflecting, to a certain extent, the main features of the pathogenesis of disease.