ABO and diabetes mellitus: More than a century has passed since the discovery of ABO system by Karl Landsteiner in 1901; this knowledge has contributed to the understanding of some mechanisms basis of heredity, and today it still has a great conceptual and clinical interest [1]; also, blood antigens had been related to predisposing individuals to some diseases like cancer, diabetes, infectious diseases, and heart illnesses [2–4] or protecting individuals against some diseases such as malaria and diabetes [5, 6].