Among the SVV and SLE groups receiving treatment with either mycophenolate or cyclophosphamide, ABCC2 expression was different by race (1.26 ± 1.82 Caucasian vs. 1.37 ± 0.86 non-Caucasian; p = 0.049); CYP2B6 expression was different by treatment (2.07 ± 2.94 cyclophosphamide vs. 0.45 ± 0.5 mycophenolate; p = 0.01). Here, CYP2B6 is linked to systemic lupus erythematosus.