Clinical, laboratory, and echocardiographic data were retrospectively analyzed in 112 patients with acute Kawasaki disease who received high-dose (2 g/kg) intravenous gamma-globulin (IVIG) treatment within 2 days and were compared for those who were responsive and non-responsive to initial IVIG treatment. Coronary arteries adjusted for body surface area (BSA) were evaluated quantitatively by comparison with the mean dimensions for 85 normal control subjects. The incidence of coronary abnormalities was higher in IVIG-non-responsive patients as compared to IVIG-responsive patients (71% versus 5%, p<0.0001). Univariate analysis of pre-IVIG data showed that the neutrophil count and serum levels of C-reactive protein (CRP), total bilirubin (TB), aspartate aminotransferase (AST), alanine aminotransferase, and lactate dehydrogenase (LDH) were significantly higher in IVIG-non-responsive versus responsive patients. Multivariate analysis selected CRP (p=0.009), TB (p<0.001), and AST (p=0.002) as independent predictors of non-responsiveness to initial IVIG treatment. By defining predictive values, patients with at least two of three predictors (CRP>or=7.0 mg, TB>or=0.9 mg, or AST>or=200 IU/L) are considered to be non-responsive to IVIG for acute Kawasaki disease. Alternatively, more intense initial therapy may be a promising therapeutic strategy for patients who are predicted to be IVIG-non-responsive.