Functional Th1-oriented T follicular helper cells that infiltrate human breast cancer promote effective adaptive immunity

J Clin Invest. 2021 Oct 1;131(19):e139905. doi: 10.1172/JCI139905.


We previously demonstrated that tumor-infiltrating lymphocytes (TIL) in human breast cancer sometimes form organized tertiary lymphoid structures (TLS) characterized by CXCL13-producing T follicular helper (Tfh) cells. The present study found that CD4+ Tfh TIL, CD8+ TIL, and TIL-B, colocalizing in TLS, all express the CXCL13 receptor CXCR5. An ex vivo functional assay determined that only activated, functional Th1-oriented Tfh TIL (PD-1hiICOSint phenotype) provide help for immunoglobulin and IFN-γ production. A functional Tfh TIL presence signals an active TLS, characterized by humoral (immunoglobulins, Ki-67+ TIL-B in active germinal centers) and cytotoxic (GZMB+CD8+ and GZMB+CD68+ TIL plus Th1 gene expression) immune responses. Analysis of active versus inactive TLS in untreated patients revealed that the former are associated with positive clinical outcomes. TLS also contain functional T follicular regulatory (Tfr) TIL, which are characterized by a CD25+CXCR5+GARP+FOXP3+ phenotype and a demethylated FOXP3 gene. Functional Tfr inhibited functional Tfh activities via a glycoprotein A repetitions predominant (GARP)-associated TGF-β-dependent mechanism. The activity of tumor-associated TLS was dictated by the relative balance between functional Tfh TIL and functional Tfr TIL. These data provide mechanistic insight into TLS processes orchestrated by functional Th1-oriented Tfh TIL, including TIL-B and CD8+ TIL activation and immunological memory generation. Tfh TIL, regulated by functional Tfr TIL, are an expected key target of PD-1/PD-L1 blockade.

Keywords: Adaptive immunity; Breast cancer; Immunology; Oncology; Th1 response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptive Immunity
  • Breast Neoplasms / immunology*
  • CD8-Positive T-Lymphocytes / immunology
  • Female
  • Humans
  • Lymphocytes, Tumor-Infiltrating / immunology*
  • Membrane Proteins / analysis
  • Membrane Proteins / physiology
  • Programmed Cell Death 1 Receptor / analysis
  • Receptors, CXCR5 / analysis
  • T Follicular Helper Cells / immunology*
  • T-Lymphocytes, Regulatory / immunology
  • Th1 Cells / immunology*


  • CXCR5 protein, human
  • LRRC32 protein, human
  • Membrane Proteins
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Receptors, CXCR5