Diabetic microangiopathy: lupus anticoagulant dependent thrombotic tendency in type 1 (insulin-dependent) diabetes mellitus.

Type 1 (insulin-dependent) diabetes mellitus is associated with long-term vascular complications. In addition to metabolic factors, immunological and haemostatic mechanisms may be involved. Lupus anticoagulant (LA), an immunoglobulin which interferes with endothelial cell function, is frequently associated with a high risk of thromboembolic events. LA has been described in several diseases but never in diabetes mellitus. The aim of this study was to evaluate if endothelial dysfunction and unmodulated haemostasis are amplified by the presence of LA in Type 1 diabetic patients. Plasma samples collected from clinically and biochemically well-characterized Type 1 diabetic patients were examined for LA, fibrinogen, prothrombin (PT), PTT, prothrombin degradation products (F1 + 2) and activated protein C (APC). The results revealed significantly decreased APC and increased F1 + 2 plasma concentrations in LA-positive but not in LA-negative patients; 60% of LA-positive and only 18% of LA-negative patients had microangiopathy (not significant). No thrombotic episodes in large vessels were found in LA-positive patients. These findings suggest that LA could be considered an additional factor in the onset and/or progression of diabetic complications, acting as a link between the immunological and haemostatic systems in the pathogenesis of diabetic microangiopathy.