Expression of PD-1 by CD4+CD25+CD127low Treg cells in the peripheral blood of lung cancer patients

Abstract

AnYuan Zhong, Xue Pan, MinHua Shi Department of Respiratory Diseases, the Second Affiliated Hospital of Soochow University, Suzhou, People’s Republic of ChinaLung cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide,1 with the majority of patients presenting with advanced disease.2 Treg cells diminish the activation and function of lymphocytes via cell-cell contact and secretion of soluble mediators.3 PD-1 is expressed on the surface of activated T and B cells and regulates their activation and proliferation.4 PD-L1 binds to the PD-1 receptor, leading to, among other responses, negative regulation of immune activity. Both Tregs and the PD-1/PD-L1 pathway play important roles in lung cancer pathogenesis;5,6 however, the association between these two factors remains poorly understood. Here, we examined PD-1 expression on Tregs, and compared these results with established clinical indicators of lung cancer. These analyses revealed significant expression of PD-1 on Tregs in lung cancer, which may be used to inform clinical diagnoses.