OBJECTIVE: This study examined the expressions of plasma stromal cell derived factor-1 (SDF-1) and CXCR4 mRNA in peripheral blood mononuclear cells (PBMC) of children with Kawasaki disease (KD) and aimed to explore the significance of SDF-1 and CXCR4 mRNA in KD. METHODS: Fifty-six children with KD (12 cases complicated by coronary artery lesions) and 60 age and gender-matched healthy children (normal controls) were enrolled in this study. Plasma SDF-1 levels and CXCR4 mRNA expression in PBMC were measured using ELISA and real-time quantitative PCR at the acute and convalescence stages of KD. RESULTS: Plasma SDF-1 levels (1 833±395 ng/L vs 1 126±408 ng/L; P<0.05) and the CXCR4 mRNA expression in PBMC (6.57±2.81 vs 2.58±1.01; P<0.01)in KD patients were significantly higher than those in normal controls at the acute stage. Both plasma SDF-1 levels and CXCR4 mRNA expression in KD patients decreased significantly at the convalescence stage, but nevertheless remained higher than those in the normal controls. The patients with concomitant coronary artery lesions showed higher CXCR4 mRNA levels than without at the acute stage (8.19±2.39 vs 6.13±2.77; P<0.05). CONCLUSIONS: Plasma SDF-1 concentration and CXCR4 mRNA expression in PBMC increased in KD patients. CXCR4 mRNA might be involved in the development of coronary artery lesions in KD.