Pernicious Anemia

Pernicious anemia (PA) is the most common cause of vitamin B12 deficiency worldwide. PA is an autoimmune disease characterized by the production of autoantibodies directed to the intrinsic factor (IF) and the parietal cells (PC) of the gastric mucosa. Pathophysiology mechanisms are still unclear, but there is evidence that supports the presence of immunoglobulins A, G, and M, as well as autoreactive T lymphocytes into gastric mucosa, blocking binding sites of cyanocobalamin and decreasing its absorption, with consequent peptic cell destruction and loss of IF. Diagnosis can be challenging because of clinical manifestations, differential diagnosis, blood test availability, serum cobalamin assay results, and titers of IF and PC antibodies. The onset of PA is progressive and insidious; the clinical features are nonspecific and are developed over 20 to 30 years. Different kinds of cyanocobalamin supplementation are now available for the management of the disease.