Aberrant NK cell phenotype in a patient with CD25 deficiency

RODRÍGUEZ BROGGI, M.G.; ZWIRNER, NORBERTO WALTER; CALDIROLA, MARÍA SOLEDAD; MOREIRA, ILEANA; BEZRODNIK, LILIANA; SEMINARIO, ANALÍA GISELA; GAILLARD, MARÍA ISABEL

Sao Paulo

Congreso; LASID 2017? (V Latinamerican Society for Immunodeficiencies Meeting); 2017

Latinamerican Society for Immunodeficiencies Meeting

INTRODUCTION: Human IL-2 receptor α chain deficiency (CD25 deficiency), caused by mutation in the IL2RA gene, is a combined immunodeficiency characterized by invasive viral and bacterial sinopulmonary infections, as well as lymphoproliferation and severe multi organ autoimmune disorders. Aim: To describe the NK cell phenotype in a patient with CD25 deficiency. MATERIAL AND METHODS: whole fresh blood and peripheral mononuclear cells from a patient with CD25 deficiency were analysed by flow cytometry in different opportunities. IFN- production by NK cells was measured after rIL-12/IL-15/IL-18 stimulation. Degranulation assay was performed using K562 target cells. Proliferation was assessed by CFSE dilution. RESULTS: the patient had normal absolute counts of NK cells with severe impairment of CD56dim/CD56bright ratio. About 50% of NK cells had a CD56++CD16+ phenotype not seen in healthy donors (HD). CD56bright cells were unable to downregulate CD62L upon activation. CD56bright cells showed high levels of perforin and granzime B as usually seen in CD56dim cells of HD. CD56bright cells produced about half percentage of IFN- than HD cells. These cells had high degranulation capacity. CD56dim cells displayed proliferative capacity when stimulated with rIL15 + rIL-2. DISCUSSION: the patient?s NK cell phenotype showed that the expression of the IL-2 receptor α chain appears to be necessary for normal NK cells development and that the aberrant phenotype of NK cells may play a role in the pathophysiology of viral infections patients with CD25 deficiency. COMMENT: the importance of extensively study our patient?s cells gives us the possibility to dissect different aspects of the biology of immune system.