Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 21 1 2022 02 06 35 43 EN Javad Poursamimi Department of Immunology, Faculty of Medicine, Zabol University of Medical Sciences, Zabol, Iran AND Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Zhaleh Shariati-Sarabi Rheumatic Diseases Research Center, Mashhad University of Medical Sciences, Mashhad, Iran AND Department of Internal Medicine, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Jalil Tavakkol-Afshari Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran AND Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Mojgan Mohammadi Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran AND Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2021 08 24 2021 10 01 Osteoarthritis (OA) is known to be the most prevalent form of joint disease. We conducted this clinical trial to investigate the effects of KrocinaTM, a natural product containing crocin, on the gene expression of unique transcription factors of various T cell subsets in patients with OA. We collected 40 peripheral blood samples of OA patients receiving Krocina™ and equal number of those who took a placebo (IRCT2015021910507N2, NCT03375814). RNA extraction was performed from the cultured peripheral blood mononuclear cells of the OA patients who received Krocina™ and placebo and SYBR Green Real-time PCR technique was applied to assess the relative gene expression of T-bet, GATA3, ROR-γt, and FOXP3 as the unique transcription factors of various T cell subsets. The relative gene expression of T-bet and ROR-γt insignificantly decreased in the Krocina™ receiving group as compared to the placebo group. In addition, the relative gene expressions of GATA-3 and FOXP3 after the treatment with KrocinaTM showed a significant and insignificant increase, respectively. Moreover, an insignificant decrease was observed in the gene expression of GATA-3 and FOXP3 in the placebo group. A significant and insignificant decrease in the gene expression of T-bet and ROR- γt was detected in the OA patients who received a placebo. GATA-3 is known as a unique transcription factor for the differentiation of T-cells to the Th2 subset. The significant increase in the gene expression of GATA-3 in the patients with OA treated with crocin may suggest the beneficial effect of crocin on shifting towards the Th2 subset and enhancing an anti-inflammatory condition. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3302 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3302/1791