<prompt> Autoimmune gastritis is associated with deficiency of vitamin?AB12CD  <response>: Ans. is b i.e., B12 In autoimmune gastritis, two important auto antibodies causing damage are anti-parietal cell antibodies most common and antibodies against intrinsic factor; anti-IF most specific. Anti-parietal cell antibodies are directed against proton pump H K ATPase. The effect of these antibodies are: -a Achlorhydria : Due to loss of parietal cells.b Vitamin B-12 deficiency and pernicious anemia : Due to deficiency of IF cells secreted by parietal cells as well as damage of IF by anti-IF antibodies.c Antral endocrine cell hyperplasia G-cell hyperplasia : Due to achlorhydria normally gastric acid has inhibitory effect on G-cells.d Reduced serum pepsinogen I: Only pepsinogen I is reduced pesinogen II is normal 