Described is a method of diagnosing, treating, or monitoring a treatment for Kawasaki disease in a subject. The method includes detecting the level of a biomarker in a sample obtained from the subject, the biomarker being IL-7F, sCD40L, MPIF-1, E-selectin, IP-10, or IL-33. The level is compared to a cut-off level. Also described is a kit for carrying out the method.