Since B lymphocyte activation can affect the expression of miRNAs, we explored whether miR-1246 downregulation in SLE patients is a consequence of B cell hyperactivity by stimulating healthy control B cells with anti-IgM in the presence of anti-CD40 or PBS (blank control), then measured miR-1246 expression by real-time RT-PCR; EBF1 protein level, AKT phosphorylation, and p53 protein levels by Western blot; and CD40, CD80, and CD86 protein levels by flow cytometry. The gene discussed is EBF1; the disease is systemic lupus erythematosus.