[Biologic response modifiers for juvenile idiopathic arthritis].

Among the subtypes of juvenile idiopathic arthritis (JIA), systemic JIA and arthritic JIA are different each other from many points of view such as clinical symptoms and course, laboratory findings, and drug response. The diagnostic process and treatment strategy should be discussed upon each characteristics. The diagnosis of arthritic JIA depends on the physical examination to reveal arthritis in each joints, blood examinations, and X-ray and MRI examination. The primary treatment includes low-dose methotrexate pulse therapy, and about 70% of the affected children will be improved. Other 30 % of children will be the objectives for the biologic response modifiers such as etanercept and infliximab. For the diagnosis of systemic JIA, clinical symptoms and signs including spiking fever pattern, skin rash, and arthritis are the first to be recognized, and pediatrician needs to exclude other febrile disease such as infectious disease, leukemia, Castleman disease, and other rheumatic diseases. For the children with systemic JIA, corticosteroids have been the only effective agents. Recently, IL-1Ra was reported to be effective for these children. Moreover, tocilizumab, anti-IL-6 receptor monoclonal antiboby developed in Japan, was revealed to be effective and safe.