The peripheral CD4 T cells predict efficacy in non-small cell lung cancer (NSCLC) patients with the anti-PD-1 treatment.

Background: Programmed cell death protein 1 (PD-1) inhibitor therapy has become a routine treatment for advanced non-small cell lung cancer (NSCLC). However, only some NSCLC patients would benefit from anti-PD-1 therapy. We urgently need to identify biomarkers associated with clinical response to change treatment strategies promptly for patients who fail to benefit from anti-PD-1 treatment. This study was aimed to explore whether circulating CD4 T cells and CD8 T cells could be biomarkers for predicting anti-PD-1 efficacy.

Methods: In this study, 118 NSCLC patients who received anti-PD-1 therapy were enrolled. The percentages of circulating CD4 T cells and CD8 T cells before and after anti-PD-1 treatment were determined by flow cytometry. The programmed cell death ligand 1 (PD-L1) expression of tumor tissues was detected by immunocytochemistry. The anti-PD-1 treatment efficacy was assessed by immune response evaluation criteria in solid tumors (iRECIST).

Results: The percentage of CD4 T cells and CD4/CD8 ratio in the peripheral blood (PB) was significantly elevated after anti-PD-1 treatment. In contrast, the percentage of CD8 T cells in the PB was significantly decreased after anti-PD-1 treatment. Furthermore, we found that the percentages of CD4 T cells and CD4/CD8 ratios considerably increased, and the percentages of CD8 T cells significantly reduced in the effective group. On the contrary, the patients in the ineffective group showed no significant differences in the biomarkers. Multivariate logistic revealed that the percentage of CD4 T cells at baseline was an independent predictor of anti-PD-1 treatment. The area under the curve (AUC) of the CD4 T cells percentage was 0.7834 with a cut-off value of 28.53% (sensitivity =82.5%, specificity =66.23%).

Conclusions: The percentage of CD4 T cells at baseline could predict anti-PD-1 efficacy in NSCLC patients.