The microRNA-200 family plays a key role in inflammatory and vascular processes, making it a relevant target for Kawasaki disease, a vasculitis with coronary complications. This study aimed to evaluate the diagnostic potential of urinary exosomal microRNA-200 family members in Kawasaki disease patients.

Urine samples from 15 Kawasaki disease patients and 15 healthy controls underwent total exosome isolation and high-throughput sequencing. Differential expression of microRNA-200 family members was validated using quantitative real-time polymerase chain reaction. Diagnostic potential was assessed via receiver operating characteristic analysis, and correlations with clinical parameters were evaluated using Spearman correlation.

High-throughput sequencing identified upregulation of microRNA-429, microRNA-200b-3p/5p, microRNA-141-3p, microRNA-200a-3p/5p, and microRNA-200c-3p in Kawasaki disease patients. We confirmed significant upregulation of microRNA-200a-3p/5p, microRNA-200b-3p/5p, and microRNA-429, with receiver operating characteristic analysis showing high diagnostic potential for these microRNAs (area under the curves of 0.844, 0.791, 0.942, 0.842, and 0.898, respectively) and a combined analysis yielding a perfect area under the curve of 1.000. MicroRNA-141 and microRNA-200c-3p/5p, however, showed no significant diagnostic value. MicroRNA-200a-3p and microRNA-200a-5p were positively correlated with white blood cells, platelet counts, and C-reactive protein, while microRNA-200b-3p and microRNA-429 were positively correlated with white blood cells, platelet counts, erythrocyte sedimentation rate, and C-reactive protein. microRNA-200b-5p showed moderate correlations with platelet counts and erythrocyte sedimentation rate.

Urinary exosomal microRNA-200 family members, especially microRNA-200a-3p/5p, microRNA-200b-3p/5p, and microRNA-429, demonstrate strong diagnostic potential for Kawasaki disease, correlating with key inflammatory markers. MicroRNA-141 and microRNA-200c did not demonstrate significant diagnostic utility.