PD-1 and PD-L1 expression on PBMC subsets in normal individuals and cancer patients
© Lepone et al.; licensee BioMed Central Ltd. 2014
Published: 6 November 2014
Immunotherapies aiming to interfere with the immune checkpoint molecule PD-1 (programmed death-1) and its ligand PD-L1 are currently being investigated in several clinical trials to treat cancer patients. The PD-1 pathway is one of the ways cancer cells evade immune-mediated killing. As little is known about the expression of PD-1 and PD-L1 in cancer patients compared to normal individuals, the aim of this study was to assess PBMC subsets for expression of these markers.
Compared to normal subjects, cancer patients had some PBMC subsets with changes in frequency but no differences in PD-1 and PD-L1 expression (i.e., B cells, mMDSCs, and gMDSCs). Other subsets showed changes in PD-1 and PD-L1 expression without differences in the frequency of the subset (i.e., CD4, Tregs, cDCs, pDCs, NK, and MDSCs). Lin-MDSCs presented at a higher frequency and greater PD-L1 positivity.
Understanding the differences of PBMC immune subsets between normal subjects and cancer patients, and the surface expression of PD-1 and PD-L1, can provide insights as to which immune subsets can be targeted by therapies aimed at interfering with the PD-1 pathway in cancer patients.
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