In our pediatric cohort, patients with SLE and RA presented an expansion of atBCs, as well as children with Fisher-Evans syndrome, immune thrombocytopenia (ITP), and autoimmune hemolytic anemia (AIHA), in which increased CD21low CD11c+ B cells were previously observed (50, 51). The gene discussed is ITGAX; the disease is autoimmune thrombocytopenic purpura.