The effect of chemotherapies on the crosstalk interaction between CD8 cytotoxic T-cells and MHC-I peptides in the microenvironment of WHO grade 4 astrocytoma.

Introduction: CD8 + T-cells and MHC-I have been detected in brain gliomas with a significant outcome. The effect of chemotherapies on the crosstalk interaction between CD8 + T-cells and MHC-I has never been explored.

Material and methods: The protein expression profiling of CD8 cytotoxic T-cells and the gene expression assay of MHC-I in 35 patients diagnosed with WHO grade 4 astrocytoma were performed. The impact of these two factors on tumor recurrence was analyzed.

Results: IDH was wildtype in 13 tumors. MHC-I protein expression was absent or low in 34 tumors and dense in a single case. MHC-I gene expression was upregulated in 10 tumors and 25 tumors showed MHC-I gene downregulation. Temozolomide (TMZ) was given to 24 patients and 11 patients received TMZ plus other chemotherapies. No statistically significant association was observed between IDH mutation and CD8 + T-cells ( p = 0.383). However, this association was significant in recurrence-free interval (RFI) ( p = 0.012). IDH-wildtype tumors with highly infiltrated CD8 + T-cells or IDH-mutant tumors with low CD8 + T-cells showed late tumor recurrence. There was a statistically significant difference in RFI between tumors with different MHC-I expression and CD8 + T-cell counts after treatment with TMZ or TMZ plus ( p = 0.026).

Conclusions: No association between IDH mutation and CD8+ cytotoxic T-cell was found. IDH is directly linked to tumor recurrence regardless of CD8 + T-cells infiltration. TMZ plus other adjuvants is proved to be more effective in improving patient survival and delaying tumor recurrence, as compared to using TMZ alone. Nonetheless, none-TMZ adjuvants may increase tumor sensitization to cytotoxic T-cells more than TMZ.