New look at chronic gastritis.

Chronic gastritis (CG) is classified as Type A (Autoimmune) and Type B [Bacterial-Helicobacter pylori (HP)]. Even Type A gastritis is initiated by HP (despite its low incidence in the gastric mucosa), as the incidence of antibodies against HP (anti-HP) in sera of patients with pernicious anemia (PA) is high. Anti-HP cross react with gastric mucosal antigens, including alpha and beta subunits of the proton pump (parietal cell antigen) and determine the damage in fundus-body and/or antral mucosa. Failure to develop intrinsic factor antibodies (IFA), determined by hereditary factors, explain the rarity of PA (despite wide prevalence of CG due to HP) in the Indian population. The necessity of separating severe chronic atrophic gastritis with histamine-fast achlorhydria from PA on the basis of absence or presence of IFA and restricting the diagnosis of PA only to those with IFA, cannot be overemphasized.