Expression of ligands of the activating receptor NKG2D in myelodysplastic syndrome and acute myelogenous leukemia blasts and lymphoid cells

FLORENCIA SECCHIARI; MÓNICA TAMASHIRO; ANDREA ZIBLAT; NORBERTO WALTER ZWIRNER; MARCELO IASTREBNER; NICOLAS IGNACIO TORRES; MERCEDES BEATRIZ FUERTES; SOL YANEL NUÑEZ; JESSICA MARIEL SIERRA; CAROLINA INES DOMAICA

Valencia

Simposio; 14th International Symposium of myelodysplastic syndromes; 2017

Different tumors express a diverse array of ligands of the NK cell activating receptor NKG2D. These molecules comprise MICA, MICB and 6 members of the ULBP family (ULBP1 to 6) and are generically known as NKG2D ligands (NKG2DLs). However, the pattern and relevance of the differential and/or combined expression of these NKG2DLs remains unknown in many cases. Nonetheless, as these molecules may constitute attractive targets for immunotherapy and potential prognostic and/or therapeutic biomarkers, a thorough characterization of the expression pattern of NKG2DLs or ?NKG2DLoma? may reveal interesting information associated with disease status, progression, response to therapy and other clinical parameters. Therefore, the aim of this study was to initiate the characterization of the NKG2DLoma expressed by peripheral blood mononuclear cells (PBMCs) from patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), as well as from healthy donors using multicolor flow cytometry. Heterogeneous expression of MICA, ULBP3 and/or ULBP4 were observed on blasts and, unexpectedly, on lymphoid cells of AML samples (n=4), compared to healthy donors (HD). In addition, only MICA and/or ULBP4 expression were observed on blasts (and in a few cases also on lymphoid cells) of MDS samples (n=7). Conversely, very low levels of NKG2DLs were observed on lymphoid cells from HD (n=12). Moreover, higher expression of MICA and ULBP3 were detected on lymphoid cells from AML samples, compared to HD (p