Decrease of interleukin (IL)17A gene expression in leucocytes and in the amount of IL-17A protein in CD4+ T cells in...

Down Syndrome is by far the most common and best known chromosomal disorder in humans. It expresses multiple systemic complications with both structural and functional defects as part of the clinical manifestation. The mechanisms of immune changes occurring in Down Syndrome are complex and include an extra gene copy of chromosome 21 and secondary dysregulation of numerous intercellular interactions. Recent studies suggest a role of interleukin 17A (IL-17A), a pro-inflammatory cytokine located on 6p12 chromosome, in the pathogenesis of inflammatory and autoimmune diseases. We aimed to analyze IL17A gene expression in peripheral white cells and IL-17A intracellular expression on CD4+ T-cells.

The research was carried out on a group of 58 children aged 6-12 years including a group of 30 children with Down Syndrome (simple trisomy of chromosome 21 only) and a reference group of 28 healthy children. We evaluated gene IL17A expression using real-time PCR and intracellular IL-17A analyzed by flow cytometry.

We found significantly decreased gene expression in white cells and significantly decreased expression of IL-17A levels on CD4+ T-cells in Down Syndrome.

Our data indicate that decreased IL-17A expression may play a significant role in the etiology of infections in Down Syndrome. Moreover, we demonstrated that in Down Syndrome the other gene located outside the extra chromosome 21 is also affected.