Comprehensive T-cell immunophenotyping and next-generation sequencing of human papillomavirus (HPV)-positive and HPV-negative head and neck squamous cell carcinomas

摘要

The success of programmed cell death 1 (PD-1) inhibition in achieving a clinical response in a subset of head and neck squamous cell carcinoma (HNSCC) patients emphasizes the need to better understand the immunobiology of HNSCC. Immunophenotyping was performed for 30 HCSCC patients [16 human papillomavirus (HPV)-positive; 14 HPV-negative] on matched tissue from the primary tumour site, locally metastatic cervical lymph nodes (LNs), uninvolved local cervical LNs, and peripheral blood. CD4(+) and CD8(+) T-cell lymphocytes obtained from tissue were analysed for expression levels of the inhibitory receptors PD-1, TIM-3 and CTLA-4. Next-generation sequencing of the T-cell receptor (TCR) chain was performed on patients (n = 9) to determine receptor repertoire diversity and for clonality analysis. HPV-negative HNSCC patients, particularly those with stage IV disease, had significantly higher proportions of CD8(+) T cells expressing CTLA-4 in tumour tissue (P = 0.0013) and in peripheral blood (P = 0.0344) than HPV-positive patients, as well as higher expression levels of TIM-3(+)PD-1(+) CD8(+) T cells (P = 0.0072) than controls. For all patients, PD-1 expression on CD8(+) T cells-particularly in HPV-negative HNSCC cases-strongly correlated (r = 0.63, P = 0.013) with tumour size at the primary site. The top CD8(+) TCR clones from tumour tissue significantly overlapped with circulating peripheral blood TCR clones (r = 0.946), and HPV-positive patients had frequently expanded TCR clones that were more hydrophobic-and potentially more immunogenic-than those from HPV-negative patients. Collectively, our findings demonstrate, for the first time, that high-stage HPV-negative HNSCC patients with primary tumours at different sites in the head and neck have elevated peripheral CTLA-4(+)CD8(+) T-cell levels, that tumour-familiar CD8(+) T cells are detectable in peripheral blood from HNSCC patients, and that TCRs from HPV-positive HNSCC patients potentially recognize distinctly immunogenic cognate antigens. However, our findings are preliminary, and need to be further confirmed in a larger patient cohort; also, how these factors affect patient response to immunotherapy needs to be determined. Copyright (C) 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.