title: Tumor-Infiltrating Merkel Cell Polyomavirus-Specific T Cells Are Diverse and Associated with Improved Patient Survival.
abstract: Tumor-infiltrating CD8+T cells are associated with improved survival of patients with Merkel cell carcinoma (MCC), an aggressive skin cancer causally linked to Merkel cell polyomavirus (MCPyV). However, CD8+T-cell infiltration is robust in only 4% to 18% of MCC tumors. We characterized the T-cell receptor (TCR) repertoire restricted to one prominent epitope of MCPyV (KLLEIAPNC, "KLL") and assessed whether TCR diversity, tumor infiltration, or T-cell avidity correlated with clinical outcome. HLA-A*02:01/KLL tetramer+CD8+T cells from MCC patient peripheral blood mononuclear cells (PBMC) and tumor-infiltrating lymphocytes (TIL) were isolated via flow cytometry. TCRβ (TRB) sequencing was performed on tetramer+cells from PBMCs or TILs (n = 14) and matched tumors (n = 12). Functional avidity of T-cell clones was determined by IFNγ production. We identified KLL tetramer+T cells in 14% of PBMC and 21% of TIL from MCC patients. TRB repertoires were strikingly diverse (397 unique TRBs were identified from 12 patients) and mostly private (only one TCRb clonotype shared between two patients). An increased fraction of KLL-specific TIL (>1.9%) was associated with significantly increased MCC-specific survival P = 0.0009). T-cell cloning from four patients identified 42 distinct KLL-specific TCRa/b pairs. T-cell clones from patients with improved MCC-specific outcomes were more avid (P < 0.05) and recognized an HLA-appropriate MCC cell line. T cells specific for a single MCPyV epitope display marked TCR diversity within and between patients. Intratumoral infiltration by MCPyV-specific T cells was associated with significantly improved MCC-specific survival, suggesting that augmenting the number or avidity of virus-specific T cells may have therapeutic benefit. Cancer Immunol Res; 5(2); 137-47. ©2017 AACR.
authors.affiliation: Dermatology/Medicine/Pathology, University of Washington, Seattle, Washington.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Miller
authors.affiliation: Dermatology/Medicine/Pathology, University of Washington, Seattle, Washington.
authors.forename: Candice D
authors.initials: CD
authors.lastname: Church
authors.affiliation: Department of Medicine/Laboratory Medicine/Global Health, University of Washington, Seattle, Washington.
authors.forename: Lichun
authors.initials: L
authors.lastname: Dong
authors.affiliation: Fred Hutchinson, Public Health Sciences Division, Seattle, Washington.
authors.forename: David
authors.initials: D
authors.lastname: Crispin
authors.affiliation: Fred Hutchinson, Public Health Sciences Division, Seattle, Washington.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Fitzgibbon
authors.affiliation: Dermatology/Medicine/Pathology, University of Washington, Seattle, Washington.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lachance
authors.affiliation: Department of Medicine/Laboratory Medicine/Global Health, University of Washington, Seattle, Washington.
authors.forename: Lichen
authors.initials: L
authors.lastname: Jing
authors.affiliation: Dermatology/Medicine/Pathology, University of Washington, Seattle, Washington.
authors.forename: Michi
authors.initials: M
authors.lastname: Shinohara
authors.affiliation: Molecular Immunology and Gene Therapy, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.|Institute of Immunology, Charité, Berlin, Germany.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Gavvovidis
authors.affiliation: Institute of Immunology, Charité, Berlin, Germany.|German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Willimsky
authors.affiliation: Fred Hutchinson, Public Health Sciences Division, Seattle, Washington.
authors.forename: Martin
authors.initials: M
authors.lastname: McIntosh
authors.affiliation: Molecular Immunology and Gene Therapy, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.|Institute of Immunology, Charité, Berlin, Germany.|Berlin Institute of Health, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Blankenstein
authors.affiliation: Department of Medicine/Laboratory Medicine/Global Health, University of Washington, Seattle, Washington. pnghiem@uw.edu viralimm@uw.edu.|Fred Hutchinson, Vaccine and Infectious Disease Division, Seattle, Washington.|Benaroya Research Institute, Seattle, Washington.
authors.forename: David M
authors.initials: DM
authors.lastname: Koelle
authors.affiliation: Dermatology/Medicine/Pathology, University of Washington, Seattle, Washington. pnghiem@uw.edu viralimm@uw.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Nghiem
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D015266:Carcinoma, Merkel Cell / Q000209:etiology* / Q000401:mortality* / Q000473:pathology; D060965:Clonal Evolution / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014644:Genetic Variation; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D059965:Merkel cell polyomavirus / Q000276:immunology*; D011379:Prognosis; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA; D012878:Skin Neoplasms / Q000209:etiology* / Q000401:mortality* / Q000473:pathology; D037182:T-Cell Antigen Receptor Specificity / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism
chemical_list: D018984:Epitopes, T-Lymphocyte; D016693:Receptors, Antigen, T-Cell, alpha-beta