Neoadjuvant Chemoimmunotherapy Increases Tumor Immune Lymphocytes Infiltration in Resectable Non-small Cell Lung Cancer

BackgroundNeoadjuvant chemoimmunotherapy treatment (NCIT) has achieved great success for non-small cell lung cancer (NSCLC); however, the intrinsic mechanism underlying this treatment remains unclear.MethodsThirty-two patients with stage IIA-IIIC NSCLC who underwent surgery after NCIT were included in this retrospective study. Multiplex immunofluorescence (mIF) staining and image analysis assays were performed on the samples collected before and after NCIT for each patient. RNA analyses was applied to confirm the mIF results.ResultsAmong the enrolled patients, 14 achieved major pathological response or pathological complete response (pCR) and were defined as the 'response' group, whereas 18 patients did not respond well to NCIT and were defined as the 'nonresponse' group. The results of the mIF assays revealed an overall increase in tumor immune lymphocytes (TILs) after NCIT in the stroma area (p = 0.03) rather than the tumor area (p = 0.86). The percentage of CD8+ T cells and tertiary lymphoid structure counts in both the response and nonresponse groups increased significantly after NCIT compared with before NCIT. CD3+ T cells and FOXP3+ cells decreased significantly in the response group but remained unchanged or increased in the nonresponse group. A comparison of the response and nonresponse groups showed that CD3, FOXP3+ and CD8+/PD-1+ cells before NCIT may serve as predictors of the response to neoadjuvant immunotherapy. The RNA analyses confirmed the mIF results that TILs were elevated after NCIT.ConclusionsThe infiltration of immune cells before NCIT was correlated with pathologic complete response, which enhanced the TILs as a promising predictor for selecting patients who were more likely to benefit from NCIT.