Abstract B082: PD-1 to CD8 ratio on tumor-infiltrating lymphocytes and peripheral blood mononuclear cells as a predictor for determining response of glioblastoma patients to radiation-induced ICD-based DC vaccine therapy

Glioblastoma multiforme (GBM) is the most common and aggressive glioma within the central nervous system in adults. Radiation-induced ICD-based DC vaccine (RICD-DC vaccine) therapy plus conventional multi-modal regimen for GBM has been demonstrated with promising outcomes in clinical trials. However, some GBM patients received RICD-DC vaccine therapy did not increased survival rates than other GBM patients who only received conventional therapy. To investigate this issue, we conducted a retrospective study to analyze clinical and laboratory data to evaluate the factors which is critical for affecting the response rate of RICD-DC vaccine treatment. Patients with de novo GBM were enrolled (n=47) and divided into two subgroups: the first subgroup received post-surgical adjuvant immunotherapy with autologous RICD-DC vaccine (n=27) and the second received conventional treatment without immunotherapy (control, n=20). Quantitative immunohistochemistry for CD45, CD4, CD8, programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1) was performed on patient tumor samples and peripheral blood mononuclear cells (PBMCs) at initial resection/biopsy before treatment. Pearson’s correlation, Cox proportional hazard model, and Kaplan-Meier analyses were performed to examine the correlations between these biomarkers expression and survival rates. In the RICD-DC vaccine group, patients with a lower PD-1+/CD8+ ratio (≤0.21) on tumor infiltrating lymphocytes (TILs) had longer overall survival (OS) (median 60.97 months, P Citation Format: Fang-Yu Lin, Chia-Ing Jan, Wan-Chen Tsai, Horng-Jyh Harn, Hsin-Man Lu, Ming-Chao Liu, Shao-Chih Chiu, Der-Yang Cho. PD-1 to CD8 ratio on tumor-infiltrating lymphocytes and peripheral blood mononuclear cells as a predictor for determining response of glioblastoma patients to radiation-induced ICD-based DC vaccine therapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B082.