title: PD-1/PD-L1 expression in human T-cell leukemia virus type 1 carriers and adult T-cell leukemia/lymphoma patients.
abstract: Adult T-cell leukemia/lymphoma (ATLL) develops after infection with human T-cell leukemia virus-1 (HTLV-1) after a long latency period. The negative regulatory programmed death-1/programmed death-1 ligand 1 (PD-1/PD-L1) pathway has been implicated in the induction of cytotoxic T-lymphocyte (CTL) exhaustion during chronic viral infection along with tumor escape from host immunity. To determine whether the PD-1/PD-L1 pathway could be involved in the establishment of persistent HTLV-1 infections and immune evasion of ATLL cells in patients, we examined PD-1/PD-L1 expression on cells from 27 asymptomatic HTLV-1 carriers (ACs) and 27 ATLL patients in comparison with cells from 18 healthy donors. PD-1 expression on HTLV-1-specific CTLs from ACs and ATLL patients was dramatically elevated. In addition, PD-1 expression was significantly higher on CD8+ T cells along with cytomegalovirus (CMV)- and Epstein-Barr virus (EBV)-specific CTLs in ATLL patients compared with ACs and control individuals. Primary ATLL cells in 21.7% of ATLL patients expressed PD-L1, whereas elevated expression was not observed in cells from ACs. Finally, in functional studies, we observed that an anti-PD-L1 antagonistic antibody upregulated HTLV-1-specific CD8+T-cell response. These observations suggest that the PD-1/PD-L1 pathway plays a role in fostering persistent HTLV-1 infections, which may further ATLL development and facilitate immune evasion by ATLL cells.
authors.affiliation: Division of Hematology and Immunology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kozako
authors.forename: M
authors.initials: M
authors.lastname: Yoshimitsu
authors.forename: H
authors.initials: H
authors.lastname: Fujiwara
authors.forename: I
authors.initials: I
authors.lastname: Masamoto
authors.forename: S
authors.initials: S
authors.lastname: Horai
authors.forename: Y
authors.initials: Y
authors.lastname: White
authors.forename: M
authors.initials: M
authors.lastname: Akimoto
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Matsushita
authors.forename: K
authors.initials: K
authors.lastname: Uozumi
authors.forename: C
authors.initials: C
authors.lastname: Tei
authors.forename: N
authors.initials: N
authors.lastname: Arima
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000276:immunology; D051017:Apoptosis Regulatory Proteins / Q000032:analysis* / Q000276:immunology; D060890:B7-H1 Antigen; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology; D016022:Case-Control Studies; D018450:Disease Progression; D015368:Human T-lymphotropic virus 1; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D061026:Programmed Cell Death 1 Receptor; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; D060890:B7-H1 Antigen; C423236:CD274 protein, human; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor