Backgroud: Kawasaki disease (KD) is a typically acute inflammatory syndrome that takes the form of systemic vasculitis. The acute inflammation and subsequent reparative process may lead to lasting changes in arterial structure even in the convalescence of KD including increased endothelial dysfunction. Endothelial microparticles (EMPs) are vesicles formed by the cell membrane after endothelial activation, and their composition can be used to characterize the status of the parent endothelial cell. EMPs were reported in cardiovascular diseases with endothelial dysfunction, such as acute coronary syndrome, pulmonary hypertension, diabetes, and vasculitis. Our aim of this study is to elucidate whether EMPs are involved in vasculitis during acute stage of Kawasaki disease.
Method: We enrolled 9 patients (aged 3 months to 14 years, 6 male, 3 female), 7 common febrile children and 5 healthy children. KD patients in the convalescent phase were divided into two subgroups; coronary artery lesion (CAL, n=2) and no coronary lesion (NCAL, n=7). Blood samples were collected at the time of diagnosis before the initiation of IVIG treatment, then immediately after the first IVIG infusion and at 2-4 weeks after disease onset. Samples were measured using flow cytometry.
Result: The percentage counts of EMPs were 2.90±1.26% in KD children before initial treatment, which were significantly higher (P<0.005) than those of disease controls (0.12±0.13%) and healthy controls (0.09±0.08%) before initial treatment, and reached normal levels within 4 weeks (0.05±0.05%). The highest percentage count of EMPs (5.47%) was observed in the patient with CAL before initial treatment. Further, prolonged high percentage count of EMPs (3.34%) was recognized in the patient with multiple gaint aneurysms at 2 weeks after onset.
Conclusion: The relation between the increased levels of EMPs and the involvement of CAL may suggest that EMPs could serve as a sensitive marker of the severity of endothelial dysfunction and vasculitis in patients with KD. Although the function of EMPs has not been fully elucidated, there is evidence that it plays an important role for distinct inflammatory reactions in endothelium.