Although independent investigations reported somewhat divergent results according to the origin of patients and probably also in connection with their treatments, in general the serum levels of CXCL12 and the expression of CXCL12 and CXCR4 in the kidneys from patients with SLE were found to be enhanced as compared to control groups, and correlated with the activity of the disease (Robak et al., 2007; Wang et al., 2010; Launay et al., 2013; Hanaoka et al., 2015; Barrera-Vargas et al., 2018), CXCR4 was found to be overexpressed on both circulating CD19+ B cells and CD4+ T-cells. The gene discussed is CD19; the disease is systemic lupus erythematosus.