MA 10.10 Tumor Draining Lymph Node Immunophenotype Corresponds with Primary Tumor Characteristics in Patients with Non-Small Cell Lung Cancer

There is growing appreciation for the role of tumor-draining lymph nodes (TDLN) in the dynamic of immuno-editing orchestrated by non-small cell lung cancers (NSCLC). By comparing T-cell subsets and gene expression in TDLN and non-draining lymph nodes (NDLN), we aim to determine whether there is tumor-regional variation in immunophenotype. Patients undergoing endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis/staging of NSCLC were recruited. Aspirates were obtained from TDLN (N1/N2 nodes with increased fluorodeoxyglucose-F-18 (FDG) avidity and/or enlarged >1cm) and NDLN (non-enlarged/non-FDG-avid N2/N3 nodes) along with peripheral blood. Samples were stained with fluorophore-conjugated antibodies (CD4-FITC, CD8-V450, CD25-PECy7, CD127-APCR700, CD45RO-PECF594) and analyzed by flow cytometry. CD4+CD25- and CD8+ effector T-cells (Teff) were sorted. Gene expression profiling was performed on sorted Teff using the Nanostring™ platform to measure differential expression between TDLN and NDLNs. We compared T-cell subpopulations in TDLN and paired NDLN from 16 subjects. There were significantly fewer CD4+ T-cells in TDLN vs NDLN (10.1% vs 28.9%, p=0.0039), with more Tregs (12.1% vs 7.3%, p=0.1563) suggesting a pattern of tumor-regional immunosuppression in the TDLN. This was more consistent when tumor histology was adenocarcinoma compared to squamous cell cancer with respect to both depletion of Teff and higher proportion of Tregs (Fig 1). A more immunosuppressive TDLN phenotype was also observed with high tumor PD-L1 expression (>50%), with 36% fewer CD4+ T-cells in TDLN relative to paired NDLN when PD-L1 expression was high relative to just 3.2% fewer CD4+ T-cells with low PD-L1 expression. Gene expression in Teff has preliminarily demonstrated upregulation of genes mediating T-cell exhaustion (CTLA-4, PD-1, TGF-β) and downregulation of co-stimulatory/recruitment factors (CD28, ICOS, ICAM2) in TDLN suggesting impaired activation of tumor-regional Teff. Our findings suggest that TDLNs in patients with NSCLC display a tolerogenic phenotype, with more marked immunosuppression in the setting of adenocarcinoma and high tumor PD-L1 expression.