Clinical Efficacy of Tumor Antigen-Pulsed DC Treatment for High-Grade Glioma Patients: Evidence from a Meta-Analysis

Background: The effectiveness of immunotherapy for high-grade glioma (HGG) patients remains controversial. To evaluate the therapeutic efficacy of dendritic cells (DCs) alone in the treatment of HGG, we performed a systematic review and meta-analysis in terms of patient survival with relevant published clinical studies. Materials and methods: A total of 409 patients, including historical cohorts, nonrandomized and randomized controls with HGG, were selected for the meta-analysis. Results: The treatment of HGG with DCs was associated with a significantly improved one-year survival (OS) (p<0.001) and 1.5-, 2-, 3-, 4-, and 5-year OS (p<0.001) compared with the non-DC group. A meta-analysis of the patient outcome data revealed that DC immunotherapy has a significant influence on progression-free survival (PFS) in HGG patients, who showed significantly improved 1-, 1.5-, 2-, 3-and 4-year PFS (p<0.001). The analysis of Karnofsky performance status (KPS) demonstrated no favorable results for DC cell therapy arm (p = 0.23). The percentages of CD3(+) CD8(+) and CD3(+) CD4(+) T cells and CD16(+) lymphocyte subset were not significantly increased in the DC group compared with the baseline levels observed before treatment (p. 0.05), whereas CD56(+) lymphocyte subset were significantly increased after DC treatment (p = 0.0001). Furthermore, the levels of IFN-gamma in the peripheral blood of HGG patients, which reflect the immune function of the patients, were significantly increased after DC immunotherapy (p<0.001). Conclusions: Thus, our meta-analysis showed that DC immunotherapy markedly prolongs survival rates and progression-free time, enhances immune function, and improves the efficacy of the treatment of HGG patients.