Following the sixth CYC dose (total 3 g), anemia persisted (Hb 114 g/L), with ongoing hematuria, pyuria, and proteinuria (4.47 g/24 h), a kidney biopsy was eventually performed after the seventh CYC dose (3.5 g total), which confirmed diffuse proliferative lupus nephritis, Class IV A/C (activity index 17/24, chronicity index 4/12). The gene discussed is GSTM1; the disease is anemia.