Phagocytic activity of blood cells in diabetic risk probands and newly diagnosed type 1 diabetics

The phagocytic activity of granulocytes and mononuclear blood cells was compared in probands at risk for insulin-dependent Type 1 diabetes mellitus and in newly diagnosed diabetics before and during short-term insulin treatment. Healthy persons without family history of Type 1 diabetes were used as controls. Furthermore, the relationship between phagocytic activity and the proportion on monocytes in the granulocyte- and mononuclear blood cell fractions was estimated. The phagocytic activity of the mononuclear cells from the risk subjects was reduced. This observation suggests that defective phagocytosis might be important in the pathogenesis of Type 1 diabetes. But the phagocytic activity of mononuclear cells from newly diagnosed diabetics was not severely impaired and was fully normal under insulin treatment. We found no differences in the phagocytic activity of the granulocytes between patients and healthy probands. The proportion of monocytes in the mononuclear cell fraction was significantly enhanced in newly diagnosed diabetics and remained high throughout the 6-month period of insulin therapy. We assume that the increased monocyte level and the phagocytic activity of mononuclear cells in diabetics are not related to each other. But the increased monocyte level could also be interpreted as a compensatory reaction against the impaired phagocytic activity observed in the risk probands.