A higher frequency of peripheral blood activated B cells in patients with non-traumatic osteonecrosis of the femoral head

B cells play important roles in inflammatory diseases. This study was aimed at examining the frequency of different subsets of B cells in patients with non-traumatic osteonecrosis of the femoral head (NONFH).The percentages of the different subsets of circulating B cells in 28 patients with steroid-related, alcohol-related, or idiopathic NONFH and 10 healthy controls (HC) were examined by flow cytometry. The concentrations of serum C-reactive protein (CRP), fibrinogen (FIB), immunoglobulins, cytokines and blood erythrocyte sedimentation rate (ESR) were measured.In comparison with those in the HC, significantly higher percentages of CD27-, CD86+, CD95+, and CD27+CD95+CD19+ but lower CD27+CD19+ B cells were detected in the patients. The percentages of CD86+, CD95+, and CD27+CD95+CD19+ B cells in each group of the patients were significantly higher than those in the HC. The levels of serum IL-17A and IFN-γ in steroid group and serum TNF-α in alcoholic group were significantly higher than those in the HC. The percentages of CD86+CD19+ B cells were positively associated with the degrees of femoral head collapse in both steroid and alcoholic groups of patients and the levels of serum TNF-α were positively associated with the degrees of femoral head collapse in the alcoholic NONFH patients.These data suggest a higher frequency of CD86+CD19+ activated B cells and elevated levels of serum TNF-α may be associated with the development of NONFH.