Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 20 6 2021 12 08 751 763 EN Reza Hajiasghar-Sharbaf Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Hossein Asgarian-Omran Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran AND Gastrointestinal Cancer Research Center, Mazandaran University of Medical Sciences, Sari, Iran Reza Valadan Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran AND Molecular and Cell-Biology Research Center, Mazandaran University of Medical Sciences, Sari, Iran Hadi Hossein-Nattaj Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Ramin Shekarriz Gastrointestinal Cancer Research Center, Mazandaran University of Medical Sciences, Sari, Iran Ehsan Zaboli Gastrointestinal Cancer Research Center, Mazandaran University of Medical Sciences, Sari, Iran Ghasem Janbabaei Gastrointestinal Cancer Research Center, Mazandaran University of Medical Sciences, Sari, Iran Mohsen Tehrani Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran AND Gastrointestinal Cancer Research Center, Mazandaran University of Medical Sciences, Sari, Iran 2020 08 22 2021 06 12 The role of immune checkpoint receptors in T-cell exhaustion has been demonstrated in several cancers. We investigated the co-expression of TIGIT/PD-1 and LAG-3/PD-1 cells in patients with chronic lymphocytic leukemia (CLL). The frequencies of TIGIT+PD-1+CD8+and LAG-3+PD-1+CD8+cells and relative mRNA expression of LSECtin and CD155 were examined in PBMCs from 33 CLL patients and 20 controls. The percentage of TIGIT+PD-1+CD8+cells was significantly higher in CLL patients than in control subjects, with the preference in advanced stage patients. However, LAG-3+PD-1+CD8+cell percentage was significantly lower in CLL patients than in the control subjects and no significant difference were found between the early and advanced stages of the disease. An increase in the mRNA expression level of LSECtin, but not that of CD155, was observed in CLL patients compared to the control subjects. Collectively, a higher co-expression of PD-1 and TIGIT on CD8+ T-cells in CLL compared to control subjects suggests an important role of TIGIT in T-cell exhaustion in CLL patients especially those with advanced disease. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/2947 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/2947/1763