Platelet factor 4, beta-thromboglobulin and thrombospondin levels in type I diabetes mellitus patients.

The proteins beta-thromboglobulin, platelet factor 4 and thrombospondin are stored in platelet alpha-granules and released from the platelet by the release reaction. The assays of these proteins were studied in patients with type I diabetes mellitus (n = 30) and a healthy control group (n = 15). Platelet factor 4 and beta-thromboglobulin levels were not significantly different in both groups but thrombospondin concentrations in diabetic patients were significantly higher than those of the control group (136.6 +/- 14.2 ng/ml vs 91.2 +/- 14.3 ng/ml, P < 0.05). When the diabetic patients were divided into those with or without complications, the diabetic patients with complications (n = 11) had significantly elevated plasma thrombospondin concentrations compared with the control group (150.4 +/- 23.7 ng/ml vs 91.2 +/- 14.3 ng/ml, P < 0.05), while thrombospondin concentrations in the control group were not statistically different from the diabetic patients without complications. Plasma beta-thromboglobulin and platelet factor 4 levels were not significantly different between the diabetic and the control group. It is suggested that thrombospondin may be a convenient marker of in vivo platelet release reaction.