Among PBC patients, 107 cases (20.66%) were serum AMA-negative, of which 25 were positive for M2 (23.36%, 25/107); 57 cases (11.00%) were serum ANA-negative, with 3 positive for gp210 and 4 positive for SP100; only 9 patients (1.74%) were negative for both AMA and ANA. The gene discussed is SP100; the disease is primary biliary cholangitis.