CD79A and systemic lupus erythematosus: DN B cells were first identified due to their expansion in patients with Systemic Lupus Erythematosus (SLE) and are considered memory B cells due to the similarity in phenotype with conventional memory B cells, presence of class-switched immunoglobulins IgG or IgA, and evidence of somatic hypermutation indicating DN cells are antigen experienced (3–5).