CXCL8^high inflammatory B cells in the peripheral blood of patients with biliary atresia are involved in disease progression

Biliary atresia (BA), the most common cause of pediatric end-stage liver disease, results from fibroinflammatory obstruction of the intrahepatic and extrahepatic bile ducts. The etiology of BA has been extensively studied, and inflammation and imbalanced immune system have been identified as the main pathogenesis of BA. B cells play roles in innate and adaptive immunity, but few studies have investigated the role of B cells in BA. This study aimed to elucidate the role of B cells in the development of BA. The percentage and numbers of total B cells (23.81 ± 11.14%，P < 0.0001, 1.22 ± 0.67 × 10⁹ L^-1 , P = 0.0014) and immature B cells (25.33 ± 14.32%, P = 0.0013, 0.19 ± 0.20 × 10⁹ L^-1 , P < 0.0001) were significantly increased in the peripheral blood of patients with BA and the number of total B cells was positively correlated with gamma-glutamyl-transpeptidase in the serum of BA. High C-X-C motif chemokine ligand 8 (CXCL8) levels were detected in the serum of patients with BA. As an important source of CXCL8, B cells from patients with BA secreted more CXCL8 into peripheral blood than those from control patients. Moreover, immature B cells can secrete more CXCL8 than mature B cells, and B cells secreted CXCL8 upon activation of the nuclear factor-κB pathway. Taken together, the results revealed that B cells have a strong ability to secrete CXCL8, which is associated with the pathogenesis of BA, and exert a proinflammatory effect on the development of BA.