NFKB2 and chronic atrophic gastritis: Mice lacking the NF‐κB1 p105/p50 subunit (Nfkb1−/−) develop gastric atrophy of greater severity than wild‐type mice following H. felis infection, whilst mice lacking the p100/p52 subunit (Nfkb2−/−) were protected from developing gastric mucosal lesions even after prolonged exposure to H. felis11.