CD55 and type 2 diabetes mellitus: In support of the findings herein constituting that mechanism, previous studies (49, 50) have shown CD55 deficiency in paroxysmal nocturnal hemoglobinuria (PNH) is associated with free nitric oxide and that expression of CD55 is decreased, like that of KLF4, on iNOS+ peripheral blood leukocytes in patients with type II diabetes.