CD4 and primary biliary cholangitis: There is a mixture of immunocompetent cells in the affected bile ducts, and CD3+, CD4+, and CD8+ T cells that bear the T-cell receptor α/β are predominant in PBC, supporting that Th1 immune response-predominant cytotoxicity and/or cytokine release are involved in the pathogenesis of the bile duct lesions of PBC.