All study cases were children enrolled from Chang Gung Memorial Hospital, Kaohsiung Medical Center, between 2001 and 2009, who fulfilled the diagnostic criteria for KD. All patients were treated with IVIG (2 g/kg) and aspirin as per our previous studies [7, 8, 18] . This study was approved by the Institutional Review Board of Chang Gung Memorial Hospital. Blood samples were collected after informed consent was obtained from parents or guardians. CAL formation was defined as the internal diameter of the coronary artery measuring at least 3 mm (4 mm if the subject was over the age of 5 years) or the internal diameter of a segment at least 1.5 times that of an adjacent segment, as observed in echocardiography [8, 22] . IVIG responsiveness was defined as defervescence within 48 h after the completion of IVIG treatment and no recurrence of fever (temperature > 38 • C) for at least 7 days after IVIG with marked improvement or normalization of inflammatory signs [7, 8] .