Utilisation of cytological samples for multiplex immunofluorescence assay

Objective Understanding the immune environment of non-small cell lung cancer (NSCLC) is important for designing effective anticancer immunotherapies. We describe the use of multiplex immunofluorescence (mIF) assays to enable characterisation of the tumour-infiltrating immune cells and their interactions, both across and within immune subtypes. Methods Six cytological samples of NSCLC taken by transoesophageal ultrasound-guided fine needle aspiration were tested with an mIF assay designed to detect the expression of key immune cell markers such as CD3, CD8, CD20, CD11b, and CD68. Pan-cytokeratin was used to detect the NSCLC cells. Fluorescence images were acquired on a Vectra-Polaris Automated Quantitative Pathology Imaging System (Akoya Biosciences). Results MIF assay was able to reliably detect and quantify the myeloid cell markers CD11b, CD68, CD3+ and CD8+ T cells, and CD20+ B lymphocytes on cytological samples of NSCLC. Whole-tissue analysis and its correlation with the corresponding H&E stains allowed a better understanding of the tissue morphology and the relationship between tumour and stroma compartments. Additionally, a uniform, specific, and correct staining pattern was seen for every immune marker. Conclusion The implementation of mIF assay on cytological samples taken with minimally invasive methods seems feasible and can be used to explore the immune environment of NSCLC.