Plasma microRNA levels in childhood IgA vasculitis.

Introduction: Immunoglobulin A vasculitis (IgAV) is the most common form of childhood systemic vasculitis. It is mostly self-limiting and characterized by skin, joint, gastrointestinal tract, and kidney involvement. Microribonucleic acids (miRNAs) are 18-25 base-long non-coding RNA group acting on gene expression. They have been shown to be effective on the immune system studies to date.

Method: In our study, 24 IgAV children with skin and joint involvement and 24 healthy children were included. Five different miRNAs (miR-33, miR-34, miR-122, miR-204, and miR451) known to be expressed in plasma and related with autoimmunity pathogenesis were evaluated. miRNAs were compared between the active period of the disease, the post-treatment period, and the healthy group using the real-time PCR method.

Results: Expression levels of miRNA-33 and miRNA-34 increased significantly in active period of the patients compare with inactive period and control groups. The expression levels of miRNA-122 and miRNA-204 decreased significantly in active period of the patients compare with other two groups. There was no significant difference in miRNA-451 levels.

Conclusions: With the experience we gained from our recent studies, we think that miRNA-204 may be a significant biomarker in autoimmune diseases. Our study is the first study between IgAV and miRNAs in children. More studies are needed to reveal this relationship. Key Points • This is the first paper to show the relationship between miRNAs and childhood IgAV. • It will provide a new perspective to evaluate the pathogenesis of the disease.