Patients with lupus followed up to normalization of CD20+ or CD19+ lymphocyte counts after a single course of rituximab required a median of 15.3 months (IQR, 12.5-27.9 months) to normalize compared with 9.4 months (IQR, 6.2-13.8 months) for other patients (Wilcoxon rank sum P = .002). The gene discussed is CD19; the disease is systemic lupus erythematosus.