Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 19 3 2020 06 23 253 263 Javad Poursamimi Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran AND Department of Immunology, Faculty of Medicine, 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 Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Seyed Ahmad Mohajeri Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran Mohsen Ghoryani Department of Laboratory Sciences, School of Paramedical Sciences, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran AND Research Center of Advanced Technologies in Medicine, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran Mojgan Mohammadi Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran AND Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2019 10 15 2019 11 05 Osteoarthritis (OA) is the major cause of joint pain and disability. This research was planned to examine the effects of Krocina™, aherbal medicine made of crocin, an ingredient of saffron, in patients with OA. Forty patients suffering from OA were enrolled in our study and randomly divided into two groups, receiving Krocina™ and placebo, and the clinical trial continued for four months.Peripheral blood was taken from all patients and the percentage ofvarious subsets of T cells in addition to the levels of forkhead box protein P3 (FOXP3) and interleukin (IL)-17 were measured by flow cytometry technique. The visualan alog scale (VAS) index analysis decreased significantly in both groups (krocinaTM and placebo) (p<0.05). Assessment of the C-reactive protein (CRP) level in serum showed a significant decrease in the krocinaTM group (p<0.05). Moreover, we found a meaningful increase in the percentage of regulatory T cells (Tregs)cellin samples gathered from Krocina™ group (P=0.02) patients. The mean percentages of T helper (Th) 17 cellsinthe Krocina™ group and CD8+ T cellsin the placebo group patients were also meaningfully reduced (p<0.05). The geometric mean fluorescence intensity (GMFI) for IL-17 showed a significant decrease and increase in Krocina™ and placebo groups, respectively (p<0.05). No noticeable difference was observed in the percentages of Th cells and GMFI-FOXP3 in either group. Treg/Th17 ratio was shifted towards Tregscell in Krocina™ group at the end of the intervention. It is concluded that Krocina™ has immunoregulatory effects on patients with OA, ameliorating the disease. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/2568