[Establishment of a 21-color Panel for the Detection of Immune Cell Subsets 
in Human Non-small Cell Lung Cancer Tumor Tissues with Flow Cytometry].

BACKGROUND: With the rise of multicolor flow cytometry, flow cytometry has become an important means to detect the immune microenvironment of lung cancer, but most of them are used to detect the proportion of cell subsets or the function of major cell subsets, and they cannot be detected at the same time. Therefore, a reliable 21-color flow cytometry protocol was established to detect the immune cell subsets in human non-small cell lung cancer (NSCLC) tumor tissues. METHODS: Cell membrane surface antibodies cluster of differentiation (CD)45, CD3, CD19, CD4, CD8, programmed cell death 1 (PD-1), CD39, CD103, CD25, CD127, chemokine receptor 8 (CCR8), CD56, CD11c, human leukocyte antigen (HLA)-DR, CD38, CD27, CD69, CD62L, CD45RA, CCR7 and nucleic acid dye L/D were used to develop the protocol. Firstly, antibody titration experiments, voltage optimization, subtraction of one color staining and single color staining experiments were carried out for each antibody, and after the experimental conditions and detection schemes were determined, the feasibility of the scheme was verified by using peripheral blood mononuclear cells (PBMCs) specimens of six healthy adult volunteers. Tumor tissue samples from 6 NSCLC patients were tested and analyzed. RESULTS: The established 21-color flow cytometry protocol was used to detect the tumor tissue samples of 6 NSCLC patients, and the proportion of each cell subset in lung cancer tissue, as well as the immunophenotype and differentiation of the main cell population, were analyzed. CONCLUSIONS: The successfully established 21-color flow cytometry protocol is suitable for the detection of PBMCs and NSCLC tissue samples, which provides an effective new idea for monitoring the immune microenvironment status in lung cancer.