Deciphering a potential causality between autoimmune atrophic gastritis and Crohn’s disease: A report of two cases

Autoimmune atrophic gastritis (AAG) is a chronic condition characterized by the atrophy of gastric oxyntic mucosa mediated by anti-parietal cells antibodies. AAG is a pre-neoplastic condition that is conducive to gastric neuroendocrine tumor type I and gastric adenocarcinoma. The diagnosis of AAG is made by a combined serological and histological profile. AAG-induced iron deficiency can lead to iron-deficiency anemia, whereas vitamin B12 deficiency can lead to pernicious anemia. Management of AAG is by replenishment of iron and vitamin B12 deficiencies and endoscopic surveillance. Crohn’s disease is an inflammatory bowel disease that can target any portion of the gastrointestinal tract, with a predilection for the ileo-colonic area. Crohn’s disease is characterized by skipped lesions and transmural involvement. We herein present two cases of AAG occurring in conjunction with Crohn’s disease, unveiling a potential causality between the two entities. • AAG and Crohn’s disease are driven by a Th1-mediated immune response • It comes as no surprise that AAG and Crohn’s disease can occur concurrently • Vitamin D deficiency may serve as an igniter to generate autoreactive T-cells via a CD4 + Th1-mediated autoimmune response