Figure 6 shows that RLR was positively correlated with the Mayo score (r = 0.522, P <.001). In PBC patients, RLR was negatively correlated with C3 (r = -0.384, P = .008) and C4 (r = -.321, P = 0.028). There was no correlation with other indexes in PBC patients (see Table 2). Further, multiple linear regression was utilized to analyze the relationship between MLR, RLR, IgA, IgG, age, sex, and Mayo score. After adjusting for other factors, RLR was the main factor affecting Mayo score (Table 3). The gene discussed is C4A; the disease is primary biliary cholangitis.