Tehran University of Medical Sciences Immunology and Genetics Journal 2645-4831 7 2 2024 06 22 72 76 Shamsolmolouk Najafi Dental Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Farzaneh Bolandparva Department of Oral Medicine, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Arezou Rezaei Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran Mohammad Javad Kharrazifard Department of Oral Medicine, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Nima Rezaei Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Stockholm, Sweden 2025 01 08 2025 01 12 Background: Recurrent aphthous stomatitis (RAS) is an inflammatory nature, while interleukin 17 (IL-17) has a pre-inflammatory role. In the present study, serum level of IL-17 was measured in a group of individuals with RAS, compared to healthy individuals. Methods: This case-control study was done on 36 patients with RAS as cases and 36 healthy subjects as controls. The level of IL-17 was measured, using ELISA method. Results: The mean serum level of IL-17 in cases was 0.14±0.21 pg/ml, which was insignificantly lower than 0.21±0.17 pg/ml in control group (p=0.12). Meanwhile there was a significant reverse correlation between age and serum level of IL-17 (r=-0.32, p=0.006). Conclusion: Although the serum level of IL-17 in RAS patients was lower than the controls, the difference was not significant. However, significantly lower serum level of IL-17 in older subjects. https://igj.tums.ac.ir/index.php/igj/article/view/164 https://igj.tums.ac.ir/index.php/igj/article/download/164/145