ABSTRACT:The aim of our study was to evaluate the efficacy of infliximab for the treatment of patients with refractory Kawasaki disease (KD) and investigate the dynamic changes of cytokines during infliximab treatment. We have performed a study of cytokine and proinflammatory molecule levels in 43 KD patients including 18 responders to IVIG, 14 nonresponders, and 11 patients treated with infliximab. We determined serum levels of soluble TNF receptor I (sTNFR I) and IL-6, as well as VEGF, damage associated molecular pattern (DAMP) molecules; myeloid-related protein (MRP)8/MRP14 and S100A12 sequentially. In eight patients, fever subsided immediately upon infliximab treatment. Four patients, who started infliximab after 12 d of illness, developed coronary artery lesions. Each of the cytokines was elevated before infliximab treatment in all patients. Although serum levels of proinflammatory cytokines decreased dramatically after infliximab treatment, DAMP molecules and VEGF and markers of local tissue damage were not suppressed. In contrast, in IVIG responders all cytokines decreased markedly after IVIG treatment. We show that infliximab is one of the adoptive therapies in refractory KD patients. Different behaviors of proinflammatory cytokines and DAMP molecules and VEGF after infliximab treatment suggest that infliximab is effective for suppression of cytokinemediated inflammation, but could not completely block local vasculitis. (Pediatr Res 65: 696-701, 2009) K awasaki disease (KD) is the most common systemic vasculitis syndrome primarily affecting small and medium-sized arteries, particularly the coronary artery. Although timely treatment with high-dose i.v. immune globulin (IVIG) is now accepted as reducing the incidence of coronary artery lesions (CAL), approximately 15% of the patients do not respond to IVIG treatment and have persistent fever as a manifestation of ongoing inflammation. These patients are at highest risk for development of CAL (1). The current practice for patients with KD and persistent or recrudescent fever after IVIG is to institute additional therapies, which may include one or more repeat doses of IVIG, high-dose pulse methylprednisoline, cyclophosphamide, methotrexate, ulinastatin, cyclosporine A (CyA), or plasmapheresis (2,3). Recently, potential new therapeutic approaches with infliximab (Remicade), a chimeric mouse-human MAb against tumor necrosis factor (TNF)-␣, have been reported in refractory KD patients (4).During the acute phase of KD, serum levels of proinflammatory cytokines such as TNF-␣ are elevated (5). In experimental studies of this syndrome, characterized by vasculitis resulting in coronary, as well as extracoronary, aneurysms, and stenosis, the attenuation of cytokine responses, especially IL-6, after infusions of IVIG may play an integral role in the rapid resolution of most of the symptoms in children with KD (6). In addition to these proinflammatory cytokines, VEGF, and markers of local inflammation of the family of damageassociated molecular pattern molecules (DAMP...