Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 16 3 2017 06 17 235 244 EN Haideh Namdari Immunology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran AND Department of Immunology, Shiraz University of Medical Sciences, Shiraz, Iran Mojgan Ghayedi Immunology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Jamshid Hadjati Immunology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Farhad Rezaei Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Kurosh Kalantar Department of Immunology, Shiraz University of Medical Sciences, Shiraz, Iran Parisa Rahimzadeh Immunology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Eisa Salehi Immunology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2016 09 08 2017 01 25 Regulatory T cells (Tregs) are important components of the immune system that modulate responses of other cells. These cells are involved in peripheral tolerance mechanisms, so defect in development and function of these cells can result in autoimmune disease. Increasing evidence supports the role of microRNAs-21 (miR-21) in the regulation of forkhead box P3 (Foxp3) expression in Tregs. We aimed to determine whether miR-21 transfection to naive CD4+ T cells can be useful in generation of iTregs in-vitro. We investigated in-vitro differentiation of miR-21-transfected naive CD4+ T cells to iTregs and compared these iTregs to cytokine-differentiated iTregs and control group. We showed that expression of Foxp3, transforming growth factor beta (TGF-β), and interleukin-10 (IL-10) are increased in iTregs generated after miR-21 transfection in comparison with cytokine-differentiated iTregs and control group. Our findings demonstrate that miR-21 has positive role in in-vitro generation of induced regulatory T-cells (iTregs).   https://ijaai.tums.ac.ir/index.php/ijaai/article/view/1047 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/1047/742