A recent retrospective study published in Frontiers in Medicine suggests that people with blood type A may be at righer risk of developing autoimmune liver diseases (AILDs), including primary biliary cholangitis (PBC).
AILDs often present with nonspecific symptoms such as jaundice, malabsorption, anemia and fever, making them harder to distinguish from other chronic conditions. Researchers have long suspected that genetic and immunologic factors contribute to disease risk, but blood type has rarely been examined as a potential contributor. This study explored whether the ABO blood group system, which influences several aspects of immune regulation, might play a role in PBC.
Read more about PBC causes and risk factors
The analysis compared 1,167 healthy people to 114 adults diagnosed with AILD, 70 of whom were noted to have PBC. The blood type of each adult was recorded and assessed for associations with disease status.
People living with PBC were found to be significantly more likely to have blood type A compared to people without autoimmune liver disease. Blood type B was found to be less common in the PBC group, while types O and AB showed no meaningful differences. These patterns were more pronounced in people with PBC than in the other AILD examined in the study, autoimmune hepatitis, suggesting that the association may be more specific to PBC.
To explain these findings, the authors pointed to known interactions between blood group antigens, immune pathways and other diseases. “Our findings suggest that ABO blood groups could potentially affect the presence of AILD,” the researchers wrote.
Overall, the results suggest that ABO blood groups may be one of several immunologic features that influence susceptibility to PBC. The authors acknowledge that larger, multi-center studies will be needed to clarify the relationship and determine whether blood type has any role in future risk assessment.
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