Low-dose Methotrexate Therapy for Intravenous Immunoglobulin-resistant Kawasaki Disease

PURPOSE: The aim of this study was to evaluate the efficacy of low-dose oral methotrexate (MTX) as a treatment for patients with Kawasaki disease (KD) which was resistant to intravenous immunoglobulin (IVIG). PATIENTS AND METHODS: The patients who had persistent or recrudescent fever after treatment with IVIG were subsequently treated with low-dose oral MTX [10 mg/body surface area (BSA)] once weekly. RESULTS: Seventeen patients developed persistent or recrudescent fever after treatment of KD with IVIG and were consequently given MTX. The proportion of children with coronary artery lesions (CALs) was 76%. The median value of maximum body temperatures decreased significantly within 24 hours of MTX therapy (38.6℃ vs. 37.0℃, p < 0.001). The median CRP (C-reactive protein) level was found to be significantly lower 1 week after administering the first dose of MTX (8.9 mg/dL vs. 1.2 mg/dL, p < 0.001). The median duration of fever before MTX treatment was shorter in CALs (-) group than in CALs (+) group (7 days vs. 10 days, p = 0.023). No adverse effects of MTX were observed. CONCLUSION: MTX treatment for IVIG-resistant KD resulted in quick resolution of fever and rapid improvement of inflammation markers without causing any adverse effects. MTX therapy should further be assessed in a multicenter, placebo-blinded trial to evaluate whether it also improves coronary artery outcome.