As described above, B cells can also act as effectors of immune response by presenting antigens and producing cytokines and significantly, the CD24hiCD38hi transitional B cell compartment which is altered in JIA also contains regulatory B cells; CD24hiCD38hi transitional B cells produce the highest amount of IL-10 following culture with agonistic anti-CD40 or CpG (10, 45). This evidence concerns the gene IL10 and juvenile idiopathic arthritis.