Clin Cancer Res.  2021  May  07.  pii:  clincanres.4394.2020. [Epub  ahead  of  print]
Céline M Laumont, 
Maartje C A Wouters, 
Julian Smazynski, 
Nicole S Gierc, 
Elizabeth A Chavez, 
Lauren C Chong, 
Shelby Thornton, 
Katy Milne, 
John R Webb, 
Christian Steidl, 
Brad H Nelson.
 
  
PURPOSE: Tumor-infiltrating lymphocytes (TIL) are strongly associated with survival in most cancers; however, the tumor-reactive subset that drives this prognostic effect remains poorly defined. CD39, CD103, and PD-1 have been independently proposed as markers of tumor-reactive CD8+ TIL in various cancers. We evaluated the phenotype, clonality and prognostic significance of TIL expressing various combinations of these markers in high-grade serous ovarian cancer (HGSC), a malignancy in need of more effective immunotherapeutic approaches.
EXPERIMENTAL DESIGN: Expression of CD39, CD103, PD-1, and other immune markers was assessed by high-dimensional flow cytometry, single-cell sequencing, and multiplex immunofluorescence of primary and matched pre/post-chemotherapy HGSC specimens.
RESULTS: Co-expression of CD39, CD103, and PD-1 ("triple-positive" phenotype) demarcated subsets of CD8+ TIL and CD4+ regulatory T cells (Tregs) with a highly activated/exhausted phenotype. Triple-positive CD8+ TIL exhibited reduced TCR diversity and expressed genes involved in both cytolytic and humoral immunity. Triple-positive Tregs exhibited higher TCR diversity and a tumor-resident phenotype. Triple-positive TIL showed superior prognostic impact relative to TIL expressing other combinations of these markers. TIGIT was uniquely upregulated on triple-positive CD8+ effector cells relative to their CD4+ Treg counterparts.
CONCLUSIONS: Co-expression of CD39, CD103, and PD-1 demarcates highly activated CD8+ and CD4+ TIL with inferred roles in cytolytic, humoral and regulatory immune functions. Triple-positive TIL demonstrate exceptional prognostic significance and express compelling targets for combination immunotherapy, including PD-1, CD39 and TIGIT.