NUP210 and primary biliary cholangitis: Sixteen of the 26 patients with PBC in the antibody-negative group were retested for autoimmune antibodies AMA, AMA-M2 antibody, anti-gp210, and anti-sp100 before and after hospitalization, with a time interval between retesting ranging from 2 months to 7 years (median was 1 year), and none of the 16 patients experienced any change of the above antibodies to positive.