For example, a study revealed the DHCQ:HCQ ratio was associated with CYP2D6*10 (rs1065852 and rs1135840) in Korean patients with lupus.14 However, few studies about CYP2C8 polymorphism were reported, and little is known about the effect of CYP polymorphisms on the concentrations of HCQ and its metabolites in Chinese patients with SLE.15 This evidence concerns the gene CYP2C8 and systemic lupus erythematosus.