PD-1 expression on peripheral CD8+ TEM/TEMRA subsets closely correlated with HCV viral load in chronic hepatitis C patients.
BACKGROUND
Tight correlation between host circulating CD8+ T cell-mediated immune response and control of viral replication is classical characteristic of long-term HCV infection. CD8+ T cell maturation/activation markers are expected to be associated with viral replication and disease progression in chronic HCV infection. The aim of the present study was to explore novel markers on CD8+ T cells with ability to evaluate HCV viral replication and disease progression.


METHODS
PBMCs were isolated from 37 chronic HCV-infected patients and 17 healthy controls. Distributed pattern of CD8+ T cells subsets and expression of PD-1, CD38, HLA-DR and CD127 were analyzed by flow cytometry. The correlation between expression of surface markers and HCV viral load or ALT was studied.


RESULTS
Declined naïve and increased TEMRA CD8+ T subsets were found in HCV-infected individuals compared with healthy controls. Percentage and MFI of PD-1, CD38 and HLA-DR on all CD8+ T cell subsets were higher in HCV-infected patients than healthy controls. In contrast, CD127 expression on CD8+ TCM showed an opposite trend as PD-1, CD38 and HLA-DR did. In chronic HCV infection, MFI of PD-1 on CD8+ TEM (p < 0.0001) and TEMRA (p = 0.0015) was positively correlated with HCV viral load while HLA-DR expression on non-naive CD8+ T cell subsets (p < 0.05) was negatively correlated with HCV viral load.


CONCLUSIONS
PD-1 level on peripheral CD8+ TEM/TEMRA was highly correlated with HCV viral load in chronic HCV-infected patients, which made PD-1 a novel indicator to evaluate HCV replication and disease progression in chronic hepatitis C patients.
Department of Microbiology, Peking University Health Science Center, Beijing 100191, PR China.
Tao
T
Shen
Jiajia
J
Zheng
Chunhui
C
Xu
Jia
J
Liu
Weidong
W
Zhang
Fengmin
F
Lu
Hui
H
Zhuang
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D015703:Antigens, CD / Q000096:biosynthesis*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis*; D015415:Biomarkers; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry* / Q000276:immunology; D002478:Cells, Cultured; D005434:Flow Cytometry; D015870:Gene Expression; D016174:Hepacivirus / Q000302:isolation & purification*; D019698:Hepatitis C, Chronic / Q000276:immunology*; D006801:Humans; D008875:Middle Aged; D061026:Programmed Cell Death 1 Receptor; D016176:T-Lymphocyte Subsets / Q000737:chemistry* / Q000276:immunology; D019562:Viral Load
D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; D015415:Biomarkers; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D000410:Alanine Transaminase