Prevalence of anti-mitochondrial antibodies and clinical features in autoimmune hepatitis (AIH) patients.

OBJECTIVE

To assess the prevalence of anti-mitochondrial antibodies (AMA) in autoimmune hepatitis (AIH) patients and to compare the clinical, biochemical, immunological, and histopathological profiles among AMA-positive AIH, AMA-negative AIH, and AIH/primary biliary cholangitis (PBC) overlap syndrome cohorts.

METHODS

A retrospective cohort study was conducted to analyze clinical data from 228 AIH patients and 227 AIH/PBC overlap syndrome patients diagnosed at Wuxi Fifth People's Hospital between 2017 and 2025.

RESULTS

The AMA prevalence among the diagnosed and probable AIH patients was 19.05% and 18.63%, respectively. AMA-positive AIH patients exhibited significantly lower AMA-M2 titers compared to AIH/PBC patients. Biochemically and immunologically, the prevalence of anti-gp210 antibodies in confirmed and probable AMA-positive AIH patients was higher than that in AMA-negative AIH patients. Confirmed AMA-positive AIH patients showed lower levels of γ-GT, ALP, and IgM compared to AIH/PBC overlap patients. Probable AMA-positive AIH patients also demonstrated reduced γ-GT and ALP levels relative to AIH/PBC overlap syndrome.Regarding clinical symptoms, definite AMA-positive AIH patients had a higher prevalence of pruritus than AMA-negative AIH patients and AIH/PBC overlap syndrome patients, and a lower prevalence of anorexia than AMA-negative AIH patients. In probable AIH patients, no statistically significant differences in clinical symptoms were observed among different AMA statuses or when compared to AIH/PBC overlap syndrome patients. Clinical symptoms across different patient groups showed varying degrees of positive or negative correlation with serological markers. Pathologically, the prevalence of bile duct injury positivity in confirmed and probable AIH patients were lower than in AIH/PBC overlap syndrome patients. The inflammatory activity levels in confirmed and probable AMA-positive AIH patients were lower than in AMA-negative patients.Serial liver biopsy results indicated that bile duct injury in AIH patients often regressed, whereas in AIH/PBC overlap syndrome patients, it predominantly persisted.

CONCLUSION

AMA positivity is not uncommon among AIH patients, and positivity for anti-gp210 antibodies may be associated with AMA status. The AIH/PBC overlap syndrome exhibits features of both conditions, characterized by more pronounced bile duct injury and cholestasis than isolated AIH.The dynamic evolution characteristics of bile duct injury can provide important pathological evidence for differentiating between the two diseases. The correlation between clinical symptoms and serological markers may offer valuable reference for assessing disease activity in AIH patients.