HP and chronic atrophic gastritis: “The patients are stratified into four categories: Group A [Hp(−)PG(−)], noninfected cases; Group B [Hp(+) PG(−)], free or mild chronic atrophic gastritis (CAG) with active or acute H. pylori infection; Group C [Hp(+) PG(+)], CAG with chronic inactive H. pylori infection; and Group D [Hp(−)PG(+)], severe CAG with extensive IM and spontaneous diminishment of H. pylori infection [26]”.