Plasma microRNA profiling of pediatric patients with immune thrombocytopenic purpura.

Immune thrombocytopenic purpura (ITP) is a commonly acquired autoimmune bleeding disorder in children. MicroRNAs (miRNAs) are small RNAs which are found in cells and circulation, and play a role in protein synthesis and regulation. In this study, we aimed to determine a biomarker for childhood ITP comparing the plasma miRNA levels of children having ITP with healthy children. A total of 86 patients with ITP and 56 healthy children followed up by the Department of Pediatric Hematology and Oncology in University of Gaziantep since July 2011 were enrolled in the study. The 86 patients with ITP were evaluated in two groups as 43 acute ITP (aITP) and 43 chronic ITP (cITP) patients. Plasma expression levels of 379 miRNAs were investigated by RT-PCR (quantitative RT-PCR) technique and they were compared between aITP, cITP, and control groups. For all miRNAs, the average of raw quantification cycle values of three groups separately in the analysis chip was accepted as the reference gene value, and normalization was done according to this value. Statistically significant differences were detected in seven miRNAs (miR-302c-3p, miR-483-5p, miR-410, miR-544a, miR-302a-3p, miR-223-3p, and miR-597) investigated between the groups with respect to the expression levels. The expression rates were found to be over 95% in miR-302c-3p and miR-483-5p, over 75% in miR-410, and over 40% in miR-544, miR-302a-3p, and miR-223-3p in all three groups. The detection of significant differences between plasma miRNA levels of aITP and cITP patients and healthy children may provide useful information in the prediction of the course of disease, determination of disease etiopathogenesis, and the development of new therapeutic modalities.