Annexin V Expression and Anti-Annexin V Antibodies in Type 1 Diabetes

Background: Annexin V (AnxV) has potent anticoagulant properties and regulatory functions for apoptosis and inflammation. Antibodies against annexin V (anti-AnxVs) may inhibit AnxV functions, leading to thrombosis during autoimmune diseases. Type 1 diabetes is an autoimmune disease and related with an ongoing autoimmune inflammation and thrombotic complications. There is no study evaluating anti-AnxVs/AnxV in a disease setting. Objective: The aim of this study was to evaluate the status of AnxV and anti-AnxVs in patients with type 1 diabetes. Methods: One hundred twenty-one patients with type 1 diabetes and 92 healthy controls were included in this study. Serum levels of AnxV and anti-AnxVs and expression of the AnxV gene and its common polymorphism in Kozak sequence (-1C>T) were studied. As a functional assay, the binding capacity of AnxV to platelets was evaluated. Results: As compared with controls, type 1 diabetic patients had significantly low serum AnxV levels and AnxV gene expression. The number of anti-AnxV positivity and their serum levels were significantly higher in type 1 diabetic patients than controls. AnxV binding to platelets were significantly decreased in the type 1 diabetic patients. The frequencies of the -1C>T polymorphism of AnxV gene did not differ between groups. Conclusions: This study demonstrated the significant changes in AnxV levels and its function in type 1 diabetic patients. These results support the hypothesis that the defective AnxV system may have a role in ongoing autoimmune activity and the development of thrombotic complications in type 1 diabetes. Further studies are necessary to elucidate the clinical impact of anti-AnxVs and dys-regulated AnxV function in type 1 diabetes.