Association between the ABO blood group and primary knee osteoarthritis: A case-control study

Recent studies have suggested association between the ABO blood group and inflammation, which was a crucial pathological process of primary knee osteoarthritis. The aim of this study was to investigate the association between the ABO blood group and primary knee osteoarthritis ​and the severity of primary knee osteoarthritis evaluated by the Kellgren/Lawrence score, as well as the histopathologic association in a subgroup of patients.

We performed a retrospective review of patients with primary knee osteoarthritis that served as the case group ​and a random sampling of healthy blood donors that served as the control group. The severity of knee osteoarthritis at the first outpatient visit was evaluated by the Kellgren/Lawrence scoring system. Further study was performed to investigate the expression of blood group antigens in synovial tissue of the knee in both cases and controls.

A total of 1126 cases and 30299 controls were involved. The proportion of AB blood group was higher in the case group than in the control group (9.7% vs. 7.8%), and logistic regression revealed that the AB blood group was a risk factor of primary knee osteoarthritis (P ​= ​0.025 and 0.048 for univariate and multivariate analysis, respectively), independent of age (P ​= ​0.973) and sex (P ​= ​0.520). Patients of the blood group AB had a higher Kellgren/Lawrence score (P ​= ​0.017). The immunohistochemical study indicated association between Le^Y antigen and primary knee osteoarthritis (P ​= ​0.029).

This study suggested that the blood group AB was associated with primary knee osteoarthritis, as well as its radiological severity. Further study indicated that Le^Y antigen, which was related to the blood group, was associated with primary knee osteoarthritis.

This study revealed that blood group AB and Le^Y antigen was associated with primary knee osteoarthritis, which shed new light on the nature of osteoarthritis, and the development of novel therapy for osteoarthritis.