TNF and juvenile idiopathic arthritis: However, since the proportion of JIA patients treated with methotrexate tended to be higher in the ANA+ than in the ANA– group (cohort 2) and none of the JIA patients was treated with TNF-α inhibitors, we do not assume that these differences in medication might explain our observation of an expanded CD21lo/− DN B cell population in the joints of ANA+ JIA patients.