Phenotypical analysis, relation to malignancy and prognostic relevance of ICOSÂ +Â T regulatory and dendritic cells in patients with gliomas

•Preoperative evaluation of DC and T cell phenotype in gliomas.•GBM demonstrate less mature DCs compared to remaining gliomas.•We show for the first time an accumulation of ICOS + Tregs/CD4 + cells in GBM.•Higher counts of CD4 + cells correlated with a better OS and PFS in GBM.•DC vaccination combined with ICOS + Tregs depletion should be considered.

We determined circulating T helper, T regulatory and ICOS + T regulatory as well as DC cell counts in 29 patients with cerebral gliomas. Samples from patients with gliomas vs. healthy controls and from patients with glioblastomas vs. patients with glioma WHO grades I-III contained significantly (p < 0.05) decreased numbers of total as well as mature, i.e. myeloid and plasmacytoid DCs. Patients with glioblastomas demonstrated significantly lower values of CD4 + as well as an increased fraction of ICOS + T regulatory/CD4 + cells. Higher CD4 + cell counts (≥ 225 cells/μl, median) were associated with improved survival in glioblastomas.