Text Box: NEUTROPHIL REDUCTION RATE AS AN INDEX OF NON-RESPONSIVENESS TO INITIAL INTRAVENOUS HIGH-DOSE GAMMA-GLOBULIN THERAPY IN PATIENTS WITH KAWASAKI DISEASE Tokuhara D1, Takaya J2, Tamada I1, Muneyuki M1, Yamamura S1, Sudou H1, Sonoda N1, Teraguchi M2 and Kobayashi Y2 1Department of Pediatrics, Matsubara Municipal Hospital, Matsubara, Japan 2Department of Pediatrics, Kansai Medical University, Moriguchi, Japan Objective: To determine the predictive values for non-responsiveness to initial intravenous gamma globulin (IVGG) therapy in patients with Kawasaki disease (KD), we analyzed laboratory data before and after the initial IVGG therapy and examined relationship between each reduction rate and non-responsiveness. Methods: Retrospective analysis of 41 patients with KD who were given IVGG (1g/kg/day x 2days or 2g/kg/day x 1day). Patients who had fever lasting for more than 48 hours or recurrent fever within 7 days after the initial IVGG treatment were identified as having IVGG non-responsiveness. Nine patients (21.9%) were non-responsive to the treatment. We compared the groups by Mann-Whitney U test with respect to the reduction rate: Reduction rate(%)=(1-laboratory value after IVGG/ laboratory value before IVGG)x100. The detected significant values were applied to a logistic regression procedure for determining the predictor. Results: The reduction rate of neutrophil, white blood cell counts and C-reactive protein were significantly lower in the non-responsive group than in the responsive group (P<0.0001, P=0.0028 and P=0.0153, respectively). The reduction rate of hematocrit was significantly higher in the non-responsive group than in the responsive group (P=0.0342). Logistic regression procedure showed the reduction rate of neutrophil count as a significant independent predictor of IVGG responsiveness (P=0.0062, R2=0.322). As a cutoff value for neutrophil reduction rate, less than 55% was found to be a significant indicator of non-responsiveness to IVGG (Odds ratio=33.8, 95% confidence interval= 4.71-242). Conclusion: The reduction rate of neutrophil count less than 55% should be considered as an index for non-responsiveness to IVGG therapy. 1172