PB2206: FULL SPECTRAL FLOW CYTOMETRY ANALYSIS OF THE BONE MARROW IMMUNE MICROENVIRONMENT IN PATIENTS WITH MYELODYSPLASTIC SYNDROME

Abstract

Background: The bone marrow (BM) microenvironment is actively studied in patients with myelodysplastic syndrome (MDS). Full-spectral flow cytometry (FSFCM) is a novel technique that makes it possible to simultaneously study the immune system and malignant cells. Aims: to study the microenvironment and immune checkpoint of MDS by FSFCM. Methods: Retrospective analysis of BM samples from 22 MDS patients and 22 healthy donors who received treatment at the Hebei Yanda Lu Daopei Hospital between January 2020 and September 2020 using 26 parameter FSFCM in a single tube. Multiple immune subsets, myeloblasts and their expression of CD96 and CD200 were also analyzed. Results: The percentage of multiple lymphocytic subsets and number of plasmacytoid dendritic cells (PDCs) were significantly significantly lower in the samples from MDS patients compared to the samples from non-malignant controls.Additionally, expression of the CD96 surface marker were significantly lower on T-cell subsets and CD56bri NK cells,and was significantly higher levels on PDCs in the MDS patient samples compared to the healthy control samples. in the MDS samples CD200 expression on immune cells and myeloblasts were significantly higher in the MDS samples compared to those from healthy controls. The overexpression of CD200 on CD56dim natural killer (NK) cells was an independent risk factor for MDS. Image:Summary/Conclusion: The percentage of immune cells and expression of immune checkpoint proteins on immune cells from BMs of MDS were distinct from that of healthy control samples.