Rheumatoid factor value for determining the first biologic agent to use for non-systemic juvenile idiopathic arthritis.

RF+ JIA required bDMARDs with high probability, therefore, early induction is ideal to relief from arthralgia. JIA with high titer of RF tends to be refractory to anti-TNFα agents. Tocilizumab or abatacept could be a first choice bDMARD in such cases.