Cytochemistry of circulating lymphocytes in diabetes mellitus with and without retinopathy and in newly diagnosed type I (insulin dependent) diabetes.

Cytochemical studies have been performed on peripheral blood lymphocytes of 68 diabetic subjects, with various conditions of metabolic control, and 15 newly diagnosed insulin-dependent diabetic patients. 20 patients of the 1 group had diabetic retinopathy. In diabetic patients periodic acid Schiff positivity, acid phosphatase, and N-acetyl-beta-glucosaminidase activities of lymphocytes are fairly impaired, particularly in insulin-dependent diabetes. Concerning the alpha-naphthyl-acetate-esterase activity, the percentage of positive cells with coarse granules is significantly reduced (p less than 0.001) in diabetic patients as compared to controls, without difference related to age and sex. These abnormalities are more evident in patients with poor glyco-metabolic control. In patients with newly diagnosed insulin-dependent diabetes we have found a further decrease in alpha-naphthyl-acetate-esterase activity, and an increase in acid phosphatase and N-acetyl-beta-glucosaminidase activities. Cyto-enzymatic activities are not significantly different in subjects with diabetic retinopathy. The results of peripheral lymphocyte enzymatic activities in diabetics could be related to a depression of the cell-mediated immunity and could enhance the infections risk of these patients. Furthermore our data show an altered immunological balance in subjects with newly diagnosed type I diabetes.