Expression of ligands of the activating receptor NKG2D in pre-malignant (myelodysplastic syndrome) and malignant (leukemia) blasts and lymphoid cells

TORRES NICOLÁS IGNACIO; FUERTES MERCEDES BEATRIZ; NUÑEZ SOL YANEL; ZIBLAT ANDREA; SECCHIARI FLORENCIA; ZWIRNER NORBERTO WALTER; SIERRA JESSICA MARIEL; DOMAICA CAROLINA INÉS

Mar del Plata

Congreso; LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA; 2016

Sociedad Argentina de Inmunología

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 leukemia (with focus on acute myelogenous leukemia) and myelodysplastic syndrome (MDS), as well as from healthy donors using multicolor flow cytometry. For leukemia patients (n=6), variable degrees of expression of MICA, MICB, ULBP2,5,6, ULBP3 and/or ULBP4 were observed on blasts and, unexpectedly, on lymphoid cells; while for MDS samples (n=5) only MICB and/or ULBP4 expression was observed on blasts (and in a few cases also on lymphoid cells). Conversely, very low levels of NKG2DLs were observed on lymphoid cells from healthy donors (n=6), while higher expression of MICA, ULBP2,5,6 and ULBP3 were expressed by lymphoid cells from leukemia samples (p