Comparison of the recommendation of international autoimmune hepatitis pathology group 2022 and the simplified criteria for autoimmune hepatitis 2008: A preliminary study.

Background and aim: The histological diagnosis of autoimmune hepatitis (AIH) is challenging. A new consensus recommendation was provided by the International AIH Pathology Group to address the problems in the histological diagnosis. The purpose of this study is to compare the 2008 'simplified' criteria for AIH with the 'consensus recommendation' of 2022 in terms of diagnostic sensitivity.

Materials and methods: A retrospective analysis was conducted on pathological specimens of patients diagnosed with Autoimmune Hepatitis (AIH) between 2010 and 2022. Out of 188 patients enlisted, 88 were selected based on exclusion criteria. The specimens were examined by two experienced hepatopathologists and a resident pathologist. All specimens were analyzed using both the "simplified" criteria and the new consensus recommendations.

Results: Out of a total of 78 patients, the 2022 consensus recommendations raised the diagnostic category of 16 patients (20.5%) to a higher level. Six patients who were previously diagnosed as "atypical" were now considered "possible AIH", while 10 patients with a "compatible" diagnosis were elevated to "likely AIH" category. No patients were found to fall into a lower diagnostic category according to the new recommendations. A significant difference in diagnostic sensitivity was observed between the 2008 criteria and the 2022 consensus report (p<0.001).

Conclusion: The 2022 consensus recommendation may be more sensitive in the diagnosis of AIH in comparison to the 2008 'simplified' histological criteria. More studies are needed both for the validation of the sensitivity of the new consensus recommendation and for the determination of the specificity.