The Usefulness of Platelet-derived Microparticle as Biomarker of Antiplatelet Therapy in Kawasaki Disease

Little is known about platelet dynamics and the effect of antiplatelet therapy in Kawasaki disease (KD). This study sought to define platelet activation dynamics in KD patients by assaying platelet-derived microparticles (PDMPs). We measured plasma PDMPs levels in 46 patients with KD using an enzyme-linked immunosorbent assay (ELISA). Blood samples were collected before, at 2–5 days, and 9–15 days after intravenous immunoglobulin (IVIG) infusion, 2 months and 4–5 months after the onset of KD. We measured PDMP levels in 23 febrile and 10 afebrile control patients. In the acute phase of KD patients, PDMP levels increased significantly after IVIG treatment (12.04 ± 5.58 nmol before IVIG infusion vs. 19.81 ± 13.21 nmol at 2–5 days after IVIG infusion, P = 0.006). PDMP levels were negatively correlated with age and positively correlated with procalcitonin levels in the acute phase of KD. No significant difference was found in PDMP levels between KD patients with and without coronary artery lesion (CAL). Elevated PDMP levels after IVIG therapy significantly decreased below the pre-IVIG level in subacute phase (19.81 ± 13.21 nmol at 2–5 days after IVIG infusion vs. 8.33 ± 2.02 nmol at 9–15 days after IVIG infusion, P < 0.001), and PDMP levels stayed below the pre-IVIG level in the convalescent phase, during which antiplatelet therapy was given. However, PDMP levels rebounded after discontinuing aspirin in 17 patients. In conclusion, enhanced platelet activation was noted before treatment of KD and peaked immediately after IVIG treatment. Recurrent rising of PDMP levels was observed after discontinuing aspirin, although there were no significant differences between the PDMP levels at 2 months after the onset of KD and those at 4–5 months after the onset of the disease.