Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 24 3 2025 05 05 304 312 Nasim Golafshani Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Narges Golafshani Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Ali Reza Mohseni Department of Laboratory Sciences, School of Allied Sciences, Mazandaran University of Medical Sciences, Sari, Iran Mahboubah Mohseni Fatemeh Zahra Hospital, Mazandaran University of Medical Sciences, Sari, Iran AND Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Ahmad Najafi Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Shervin Ziabakhsh-Tabari Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Hossein Asgarian-Omran Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Mohsen Tehrani Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Aliakbar Pourfathollah Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran 2024 01 24 2024 05 12 Blood transfusion is associated with increased mortality and morbidity. This study aimed to determine the effect of blood transfusion on T-helper 1 (TH1), TH2, and TH17 function in patients undergoing coronary artery bypass grafting (CABG). Two blood samples were obtained from patients undergoing CABG, before and 14 days after surgery. Production of interleukin (IL)-2, IL-4, interferon (IFN)-γ, IL-17A, and IL-10 by CD4+ T cells was measured using enzyme-linked immunosorbent assay (ELISA). mRNA expression of T-box expressed in T cells (T-bet), GATA binding protein 3 (GATA3), RAR-related orphan receptor-γ (ROR-γt), signal transducer and activator of transcription 3 (STAT3), STAT4, and STAT6 were measured using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). mRNA expression of T-bet and STAT4 showed a significant decrease after blood transfusion. However, the concentration of IFN-γ in the culture supernatant showed no significant difference after blood transfusion. mRNA expression of GATA3 and STAT6 showed a significant decrease after blood transfusion. However, the concentration of IL-4 in the culture supernatant showed no significant difference after blood transfusion. mRNA expression of ROR-γt showed no significant decrease after blood transfusion; however, the expression of STAT3 and the concentration of IL-4 in the culture supernatant did significantly decrease following blood transfusion. IL-10 production increased significantly postoperatively. Decreased TH1, TH2, and TH17 signaling pathway activity and increased IL-10 concentration indicate an immunomodulatory effect on the immune system after blood transfusion. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4010 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4010/2151