Autoimmune gastritis (AIG) is categorized into three phases, histologically, based on the severity of oxyntic mucosal atrophy. These include the early, florid, and end phases. A study was recently conducted to ascertain the relationship between these phases and the anti-parietal cell antibody titer.

Patients undergoing upper gastrointestinal endoscopy were retrospectively reviewed and those with a histologic diagnosis of AIG were included in the study. They were subjected to serologic testing for anti-parietal cell antibody (APCA). AIG patients were segregated into three groups - early, florid, and end phase groups, and the clinical characteristics, including APCA titers, were compared among the groups.

In all, 44 AIG patients were included in the study. Two patients were there in the early phase, 11 in the florid phase, and 31 in the end phase.

• APCA-positive rates in early, florid and end phase were 100%, 90.9%, and 90.3%, respectively.
• The mean APCA titers in the three phases were 480 U, 220 U, and 150 U, respectively.
• A stepwise decline in the APCA titer was noted from the early phase to the end phase.
• Mean APCA titer for end phase was significantly lower than the early or the florid phase.
• There was a stepwise reduction in serum gastrin levels as well from the early phase to the end phase.

To conclude, AIG progresses from the early to the end phase, and the APCA titer shows a decline.

Negativity of APCA could occur, particularly in the end phase.

Source: Nishizawa T, Watanabe H, Yoshida S, et al. Decreased anti-parietal cell antibody titer in the advanced phase of autoimmune gastritis. Scand J Gastroenterol. 2022 Feb;57(2):143-148.