Identification and validation of differential expression of miR-455-5p in plasma of children with Kawasaki disease.

Objectives: To provide clues for further study of the relationship between miRNAs and Kawasaki disease (KD) development, and to provide molecular markers for ultimately improve the rate of early diagnosis for KD.
Methods: We collected acute, recovery KD children's plasma and normal samples, then used the miRNAs Assay Chip to screen the differentially expressed miRNAs in the plasma from KD children. Subsequently, miR-455-5p, which had identified via miRNAs assay chip, was validated by quantitative real-time PCR via independent cohort.
Results: According to the results of miRNAs Assay chip, we identified a miRNAs panel including 5 miRNAs significantly up-regulated and 5 miRNAs remarkably down-regulated in the plasma from KD children compared to the normal control; miR-455-5p in both of acute and recovery KD children's plasma was remarkably lower than that in the normal control ( P <0.001, P =0.013, respectively), and miR-455-5p was also significantly lower than that in the recovery of KD children ( P =0.007) by independent cohort validation.
Conclusions: There are significantly differentially expressed circulating miRNAs between the KD children and normal control. We identified 10 miRNAs dysregulation in the KD children's plasma compared with the normal group. Circulating miR-455-5p in both of acute and recovery KD children's plasma is remarkably lower than that in the normal control, and miR-455-5p may considered as a marker to show the recovery process of KD children. Plasma specific circulating miRNAs play an important role in the early diagnosis of KD and become the new molecular marker of KD in the future.