C4A and primary biliary cholangitis: In addition, the serum levels of C4 in noncirrhotic PBC-AIH OS patients were significantly decreased than those in healthy control individuals (11.24 ± 3.82 vs. 17.98 ± 3.04 ng/mL; p = 0.015) and the serum levels of C4 in cirrhotic PBC-AIH OS patients were significantly decreased than those in healthy control individuals (1.61 ± 0.51 vs. 17.98 ± 3.04 ng/mL; p < 0.001) and noncirrhotic PBC-AIH OS patients (1.61 ± 0.51 vs. 11.24 ± 3.82 ng/mL; p = 0.004) (Table 1) (Figure 1(d)).