Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 21 1 2022 02 06 86 91 Fatemeh Mansouri Department of Genetics and Immunology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran AND Cellular and Molecular Research Center, Urmia University of Medical Sciences, Urmia, Iran Mir Hosein Seyed Mohammadzad Department of Cardiology, Seyedoshohada Hospital, Urmia University of Medical Sciences, Urmia, Iran 2021 01 06 2021 06 30 Cardiovascular diseases are the most prevalent disease worldwide and pose a considerable threat to human health. Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) plays a crucial role in the maintenance of immune diseases; however, its role in the progression of cardiovascular disorders is still unknown. The present study aimed to evaluate the relationship between CTLA-4 and myocardial infarction (MI). The Kyoto encyclopedia of genes and genomes database and the pathway studio database has revealed the role of CTLA4 as an inhibitory receptor on activated T cells. The relative expression of the CTLA-4 gene was assessed on the peripheral blood cells in 80 MI patients and 80 healthy individuals using quantitative real-time polymerase chain reaction (qRT-PCR) and also receiver operating characteristic (ROC) analysis was performed to evaluate the sensitivity and specificity of CTLA-4. We noticed the decreased expression of CTLA-4 levels in patients, compared to the control group (2.73±1.55 vs. 5.36±1.34). The study revealed the sensitivity of 0.89, specificity of 0.83, the accuracy of 0.9, and the area under the ROC curve (AUC) of 0.901 (95% CI: 0.727-0.776) for CTLA-4. The results highlighted the critical role of CTLA-4 as an inhibitory receptor in the maintenance of cardiovascular risks. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/3089 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/3089/1797