IFNAR2 and systemic lupus erythematosus: Moreover, severe SLE patients showed higher serum levels of IFN-α (Fig. 5C, P < 0.0001) and IFNAR1/R2 expression than the mild/moderate SLE patients (Fig. 5D; IFNAR1: P < 0.0001 and IFNAR2: P < 0.0001).