Immune Spatial Differences Between Short and Long-term Surviving Glioblastoma Patients

Abstract Introduction: Immune surveillance, distribution, interactions, and antigen presentation within the tumor microenvironment (TME) may influence anti-tumor reactivity and survival. Methods: Dichotomized newly diagnosed treatment-naïve IDH1 wild-type glioblastoma, negative MGMT promotor methylation (65%), short-term (STS; ≤ 6 months; mean age 66 years; n=10) or long-term (LTS; >2 years; mean age 50 years; n=10) survivors, were profiled using high dimensional fluorescence multiplex staining spatial analysis of the TME using a panel of 26 markers. Results: The amounts of specific immune cells (CD4 +, CD8 +, FOXP3 +, CD11c +, CD20 +, CD68 +, CD205 +, NKG2D +) were similar between cohorts, except STS were enriched with CD163 +expressing macrophages and LTS had more P2RY12 +microglia throughout the TME. There was minimal MHC-I expression and no difference in MHC-II on the myeloid populations (CD68 +, CD11c +, CD163 +, P2RY12 +, and/or in combination) in both cohorts. TIM-3 was the only immune regulator substantially expressed on P2RY12 +microglia and the other myeloid populations, irrespective of survival. Perivascular clustering of CD11c +CD163 +cells was enriched in STS cases. The TME in LTS cases demonstrated adaptive immune activation processes, including CD11c +P2RY12 +CD205 +microglia interacting with CD45RO −naïve, non-exhausted (PD-1 −, LAG3 −, Tim3 −) CD8 +T cells expressing the LCK +immune synaptic marker. Conclusion: Immune activation interactions between CD8+ T cells and microglia in the TME may help determine STS versus LTS in GBM patients.