NK cells, particularly CD56bright NK cells, can, by production of GM-CSF and CD154, induce CD14+ monocyte differentiation into DCs in RA and psoriatic arthritis but not osteoarthritis OA patients.330 Therefore, RA NK cells provide a local milieu for monocytes to differentiate into DCs and sustain the disease. The gene discussed is CD40LG; the disease is psoriatic arthritis.