We aimed to investigate STAT3 phosphorylation in CD4+ and CD8+ T cells and CD11b+ myeloid cells from patients with SLE using single-cell flow cytometry of peripheral blood mononuclear cells (PBMCs) stimulated ex vivo with interleukin-6 (IL-6) or IL-15. This evidence concerns the gene IL15 and systemic lupus erythematosus.