The classification of type I and type II diabetes mellitus has been made under the guidance of the World Health Organization (WHO). Type I or insulin dependent diabetes mellitus (IDDM) is characterized by absolute insulin deficiency due to an autoimmune destructive process of the β-cell in the islets of Langerhans. The main clinical symptoms for IDDM are thirst, polyuria and acidosis. Antibodies to islets cells are found, while indications of residual insulin production (the so-called C-peptide levels) appear at low levels at the onset of the disease. Type I diabetes can develop at any age (often below 30 years old). Genetic factors seem to predispose for the susceptibility to develop the autoimmune insulitis by viral or other toxic causes....