Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 59 7 2021 08 25 400 405 Reza Hajebi Department of General Surgery, Sina Hospital, Tehran University of Medical Sciences, Tehran,.Iran . AND School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Ali Ajam Students’ Scientific Research Center (SSRC), School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Shahrokh Karbalai School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. AND Department of Cardiology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran Haleh Ashraf Research Development Center, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran 6 Cardiac Primary Prevention Research Center (CPPRC), Cardiovascular Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Ostadali Dehaghi Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran. AND Cell Therapy and Hematopoietic Stem Cells Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran Hedieh Moradi Tabriz School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. ANDDepartment of Pathology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran. Marzieh Pazoki Department of Internal Medicine, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran Fatemeh Khalili School of Medicine, Arak University of Medical Sciences, Arak, Iran 2021 03 16 2021 04 16 In the last days of 2019, a new coronavirus emerged in Wuhan, China, and less than three months its disease, now called COVID-19, was announced a global pandemic by WHO. COVID-19 usually causes respiratory symptoms and can lead to more severe conditions like ARDS. HLA has a crucial role in regulating the immune system; thus, different HLA allele types can be a protective or risk factor for some diseases, so we aimed to find such associations to determine whether some alleles can predict susceptibility or resistibility to COVID-19 and finally facilitate vaccine development. In this case-control study, 15 admitted COVID-19 cases with severe symptoms and ten individuals with mild COVID-19 symptoms were enrolled in the case and control groups, respectively. They were genotyped for HLA A/B/DR loci using a low-resolution HLA typing test. These alleles were more prevalent in case (severe COVID-19) group: A*24 (53.33% vs 10%), B*50 (20% vs 10%), B*55 (20% vs 10%), DRB1*04 (40% vs 20%) and DRB1*11 (53.33% vs 30%) but the difference was only statically significant in A*24 allele (P=0.027; odd ratio=10.286). A*24 was also more prevalent in all patients than the general population in Iran. A*24 was the only allele more prevalent in severe COVID-19 cases with statistical significance. This allele was reported to be a risk factor for such autoimmune diseases as type 1 diabetes, myasthenia gravis, and systemic lupus erythematosus, which may be related to reported immune system hyperresponsiveness in severe COVID-19 cases. https://acta.tums.ac.ir/index.php/acta/article/view/9241