Fc and C3b receptor expression of phagocytes in poorly controlled diabetic patients

Attachment, an energy-independent step, of sensitized sheep erythrocytes EA and EAC to Fc and C3b receptors, respectively, on granulocytes and monocytes from poorly controlled diabetic patients was investigated. The results show similar percentages of EA and EAC rosette-forming cells for normal and diabetic human neutrophils. The expression of Fc receptors on normal and diabetic monocytes were also similar in that the former contained 74.5 +/- 9.3% and the latter contained 66.0 +/- 9.4% rosette-forming cells. However, a significantly lower percentage (48.3 +/- 15.2%) of EAC rosette positive cells was found in diabetic monocytes as compared to that (68.1 +/- 8.2%) found in normal controls (p less than 0.001). Incubation of diabetic monocytes with insulin or serum obtained from normal individuals one hour prior to assay corrected the impaired expression of C3b receptors in diabetic monocytes. In addition, we also found that diabetic serum itself is noxious to C3b receptor expression by normal human monocytes and that high concentrations of glucose play no apparent role in the regulation of the receptor function.