A Prospective Exploratory Study of Functional Immunity Assessed by Pretreatment Interferon Gamma Release Assay in Relation to Different Systemic Therapies in Patients With Advanced-Stage NSCLC

Introduction

Predictive markers for chemotherapy and immunotherapy response in advanced NSCLC are limited, and no objective tool exists to assess immune function, which is critical for treatment outcomes. This study prospectively evaluated the interferon gamma (IFN-γ) release assay (IGRA) as a potential predictor of treatment response and a tool for assessing immune function.

Methods

We enrolled patients with stage IV NSCLC undergoing first-line chemotherapy, EGFR tyrosine kinase inhibitor (TKI) therapy, or any line of single-agent immunotherapy, alongside stage I controls. Peripheral blood samples were collected pre- and post-treatment for IGRA testing using the QuantiFERON-TB Gold In-Tube (QFT-GIT) kit. Phytohemagglutinin-stimulated IFN-γ (PSIG) responses were measured by both QFT-GIT and in-house enzyme-linked immunosorbent assay, with stage IV patients categorized into high- and low-PSIG response groups based on median pretreatment values.

Results

A total of 117 patients were analyzed (32 surgery, 30 EGFR TKI, 25 chemotherapy, 30 immunotherapy). The median PSIG response was significantly higher in stage I patients than stage IV (1420 pg/mL versus 960 pg/mL; p = 0.032). In stage IV, those with driver mutations had higher pretreatment PSIG responses (1278 pg/mL versus 288 pg/mL; p = 0.004). Kaplan–Meier analysis suggested a trend toward longer progression-free and overall survival in the EGFR TKI and immunotherapy groups with higher PSIG responses, though not statistically significant.

Conclusions

Patients with advanced-stage NSCLC exhibited reduced lymphocyte function, and patients with driver mutations correlated to less exhausted lymphocyte. IGRA demonstrates potential as a clinical tool for assessing immune function in these patients.