Monitoring of regulatory T cell frequencies and expression of CTLA-4 on T cells, before and after DC vaccination, can predict survival in GBM patients

PLoS One. 2012;7(4):e32614. doi: 10.1371/journal.pone.0032614. Epub 2012 Apr 2.


Purpose: Dendritic cell (DC) vaccines have recently emerged as an innovative therapeutic option for glioblastoma patients. To identify novel surrogates of anti-tumor immune responsiveness, we studied the dynamic expression of activation and inhibitory markers on peripheral blood lymphocyte (PBL) subsets in glioblastoma patients treated with DC vaccination at UCLA.

Experimental design: Pre-treatment and post-treatment PBL from 24 patients enrolled in two Phase I clinical trials of dendritic cell immunotherapy were stained and analyzed using flow cytometry. A univariate Cox proportional hazards model was utilized to investigate the association between continuous immune monitoring variables and survival. Finally, the immune monitoring variables were dichotomized and a recursive partitioning survival tree was built to obtain cut-off values predictive of survival.

Results: The change in regulatory T cell (CD3(+)CD4(+)CD25(+)CD127(low)) frequency in PBL was significantly associated with survival (p = 0.0228; hazard ratio = 3.623) after DC vaccination. Furthermore, the dynamic expression of the negative co-stimulatory molecule, CTLA-4, was also significantly associated with survival on CD3(+)CD4(+) T cells (p = 0.0191; hazard ratio = 2.840) and CD3(+)CD8(+) T cells (p = 0.0273; hazard ratio = 2.690), while that of activation markers (CD25, CD69) was not. Finally, a recursive partitioning tree algorithm was utilized to dichotomize the post/pre fold change immune monitoring variables. The resultant cut-off values from these immune monitoring variables could effectively segregate these patients into groups with significantly different overall survival curves.

Conclusions: Our results suggest that monitoring the change in regulatory T cell frequencies and dynamic expression of the negative co-stimulatory molecules on peripheral blood T cells, before and after DC vaccination, may predict survival. The cut-off point generated from these data can be utilized in future prospective immunotherapy trials to further evaluate its predictive validity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Brain Neoplasms / mortality
  • Brain Neoplasms / pathology*
  • Brain Neoplasms / therapy
  • CTLA-4 Antigen / genetics
  • CTLA-4 Antigen / metabolism*
  • Cancer Vaccines / administration & dosage*
  • Cell Extracts / immunology
  • Clinical Trials, Phase I as Topic
  • Dendritic Cells / immunology*
  • Dendritic Cells / transplantation
  • Female
  • Glioblastoma / mortality
  • Glioblastoma / pathology*
  • Glioblastoma / therapy
  • Humans
  • Kaplan-Meier Estimate
  • Lymphocyte Activation
  • Lymphocyte Count
  • Lymphocyte Subsets
  • Male
  • Middle Aged
  • Proportional Hazards Models
  • T-Lymphocytes, Regulatory / metabolism*
  • Treatment Outcome
  • Vaccination*
  • alpha-Glucosidases / immunology


  • CTLA-4 Antigen
  • Cancer Vaccines
  • Cell Extracts
  • GAA protein, human
  • alpha-Glucosidases