Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 0 0 2026 05 17 1 13 Nima Jadidian Tuberculosis and Lung Disease Research Center of Tabriz University of Medical Sciences, Tabriz, Iran AND Department of Internal Medicine, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Ali Hazrati Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Arsalan yazdchi Student Research Committee, Tehran University of Medical Sciences, Tehran, Iran Hamed Valizadeh Tuberculosis and Lung Disease Research Center of Tabriz University of Medical Sciences, Tabriz, Iran AND Department of Internal Medicine, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad Reza Taban-Sadeghi Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Majid Ahmadi Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Haleh Mikaeili Tuberculosis and Lung Disease Research Center of Tabriz University of Medical Sciences, Tabriz, Iran 2 Department of Internal Medicine, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 2025 10 21 2026 01 25 The airflow limitation is one of the characteristics of chronic obstructive pulmonary disease (COPD), which is not entirely reversible. It seems that factors such as inflammation, hypoxia, and remodeling of pulmonary vessels can increase pulmonary hypertension (PH). This increase in pulmonary arterial hypertension leads to aggravation of disease complications. Considering the role of immune cells in causing pathological inflammation in the pathogenesis of COPD, it seems that Th17/Treg axis imbalance can be one of the main reasons for the difference in life expectancy in patients with COPD with and without PH. By measuring and comparing some inflammatory biomarkers in patients with COPD with and without PH, this study tries to introduce these biomarkers to predict the occurrence or nonoccurrence of this complication. This study aims to compare the ratio and activity of Th17 to Treg in patients with COPD with high (20 patients) and normal (20 patients) pulmonary arterial pressure. Five milliliters of blood containing anticoagulant were obtained to isolate peripheral blood mononuclear cells (PBMCs). Then, the ratio of Th17 to Treg, their number, and their activity were evaluated by ELISA, real-time polymerase chain reaction (PCR), and flow cytometry. Our results show that the amount of inflammatory factors and the population of Th17 cells in patients with COPD with PH is associated with a significant increase in PH compared to patients with COPD without PH, which leads to damage caused by pathological inflammation to the lung tissue and a decrease in the overall survival of the patients. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4639 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4639/2338