[Analysis of the Correlation between Immune Cell Subsets in Bronchoalveolar Lavage Fluid and the Efficacy of First-line Use of Immunotherapy in Advanced Non-small Cell Lung Cancer: A Case-control Study].

Background: Immunotherapy has been a standard treatment for the patients with advanced non-small cell lung cancer (NSCLC), however, reliable biomarkers for predicting the response remain unclear. This study explores the subpopulations of lymphocytes in bronchoalveolar lavage fluid (BALF) and combines clinical and laboratory examination indicators of NSCLC patients to identify potential biomarkers related to immunotherapy.

Methods: A retrospective analysis was conducted on 82 patients with locally advanced or metastatic NSCLC who underwent electronic bronchoscopy and received first-line immunotherapy at Beijing Chest Hospital, Capital Medical University between March 2020 and November 2022. Logistic regression and random forest models were employed to determine the correlation between immune cell subsets in BALF and response of immunotherapy. The predictive value was validated by the model.

Results: All patients enrolled received first-line immunotherapy, and the efficacy was evaluated according to clinical guidelines: among the 82 patients included, 48 patients got objective response and the other 34 did not achieve. The relationship between collected indicators and the best clinical treatment response was analyzed. The result shows that a higher percentage of total lymphocytes in BALF was associated with good response of first-line immunotherapy (P<0.05), while a higher percentage of T helper cells in BALF was associated with poor prognosis (P<0.05).

Conclusions: The proportions of total lymphocytes and T helper cells in BALF could be used as predictive biomarkers for first-line immunotherapy in late stage NSCLC. A multivariable model improves predictive accuracy.