Association between ABO blood group system and autoimmune liver disease.

Background: Autoimmune liver disease (AILD) is a chronic inflammatory liver disease mediated by abnormal autoimmune response, and its pathogenesis has not been fully elucidated. Studies have shown that ABO blood is associated with autoimmune diseases, but the relationship between ABO blood groups and AILD has not been studied. The purpose of this study is to examine whether there is a correlation between ABO blood group and AILD. Methods: A retrospective cohort study was conducted on 114 AILD patients and 1,167 healthy individuals from January 2019 to February 2024. Blood type was determined with the gel microcolumn assay. Chi-square test and logistic regression were performed to investigate the association between blood type and the risk of AILD. Results: Of 114 patients, 44 (38.60%) were diagnosed with autoimmune hepatitis (AIH), and 70 (61.40%) were diagnosed with primary biliary cholangitis (PBC). A significant difference was found between ABO blood groups and AILD patients. Compared with the controls, blood type A was more prevalent in the AILD group (OR, 1.784; p < 0.05), whereas blood type B was less (OR, 0.638; p < 0.05). Moreover, patients with PBC had a higher percentage of type A (OR, 2.656; p < 0.01) and a lower percentage of type B (OR, 0.514; p < 0.05). No significant difference was found in blood type O and AB (p > 0.05). Conclusion: Our findings suggest that ABO blood groups could potentially affect the presence of AILD.