Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 17 6 2018 12 03 557 563 EN Mansour Arab Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Maryam Razzaghy-Azar Aliasghar Children's Hospital, Iran University of Medical Sciences, Tehran, Iran AND Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran Zahra Salehi Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Maryam Keshavarz Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran AND Department of Quality Control, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran Ensieh Nasli- Esfahani Endocrinology and Metabolism Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran Mahdi Shekarabi Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Maryam Izad Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2017 08 20 2017 12 05 Type 1 diabetes (T1D) is an autoimmune disease resulting from the damage of pancreatic B-cells mediated by autoreactive CD4+ and CD8+ T cells. In recent years, follicular T helper (Tfh) cells have been recognized as a subpopulation of CD4+ T cells providing help for B cells differentiation and antibody production. In this study, we examined the frequency of circulating CD4+CXCR5+ and CD4+CXCR5+ICOS+ (representing Tfh) cells as well as serum levels of anti-glutamic acid decarboxylase 65 (GAD65) and islet cell autoantibodies (ICA) in children with type I diabetes. We analyzed the percentage of Tfh cells within peripheral blood mononuclear cells in 20 children with T1D (≤300 days from disease onset; Mean age 6.8±4.6 years) and 18 healthy individuals (Mean age 8.8±2.2 years) using flow cytometry. Anti-glutamic acid decarboxylase (GAD) and islet-cell cytoplasmic autoantibodies (ICA) levels were determined by ELISA and indirect immunofluorescence respectively. We found that the frequency of CD4+CXCR5+ and CD4+CXCR5+ICOS+ (Tfh) cells were significantly increased in the peripheral blood of patients compared with healthy controls (p<0.001). Furthermore, elevated levels of anti-GAD and ICA antibodies were detected in children with T1D (p=0.001 and p=0.02 respectively). There was no correlation between Tfh cells frequency and the autoantibody levels. The results of our study indicate an increased frequency of Tfh cells in children With T1D that could suggest a possible role of these cells in the disease pathogenesis. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/1633 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/1633/1380