CHARACTERIZATION OF MEMORY NK CELL SUBPOPULATION IN HER2+ BREAST CANCER (BC) PATIENTS

ROMANO, SOFIA; PINKASZ, MARINA; JULIÁ, ESTEFANÍA; OSTINELLI, ALEXIS; CUETO, GERARDO; SANCHEZ, MARIA BELÉN; CRIMI, GABRIEL; MC LEAN, IGNACIO; COLÓ, FEDERICO; MORDOH, JOSÉ; MANDÓ PABLO; LEVY, ESTRELLA

San Miguel de Tucumán

Congreso; LXVII Reunión Científica Anual de la Sociedad Argentina de Inmunología; 2019

Recently, a NK cells subpopulation has been described as "memory-like" (NKm). NKm cells have been initially identified in healthy HCMV-seropositive individuals, mainly based on high expression levels of CD94/NKG2C and CD57 receptors. HCMV-associated NK cells also exhibit a distinct surface receptor expression pattern, consisting of a reduced expression of NKG2A, NKp30, NKp46, and CD16. Despite the lower CD16 expression, they have been shown to efficiently mediate degranulation and IFN-γ production, upon stimulation via antibody-opsonized targets, rendering NKm cells an attractive tool for antitumor immunotherapy. Despite remarkable progress in this field, NKm has been poorly described in cancer patients.Wondering the implications of NKm subpopulation in anti HER2+ antibody-therapy, we analyzed by FACS 8 NK cells receptors on peripheral blood mononuclear cells of 25 female patients diagnosed with HER2+ Breast Cancer (BC) before trastuzumab and pertuzumab neoadjuvant therapy, and 11 healthy donors (HD) to characterize their NKm phenotype. Preliminary results showed that HCMV+ frequency in patients are similar to HD´s (80 vs. 73% respectively). We determined that only HCMV+ BC patients showed a NKG2C percentage higher than 20%, which is coincident with reported in HD. Moreover, NK cells from HCMV+ patients showed significantly higher expression of CD57 (median 68% vs 51%; p value=0.0342 non-parametric t-test) and lower of NKp30 (92% vs 98%; p value=0.0004 non-parametric t-test) than HCMV- ones, which matches with previous descriptions of NKm subpopulation in HDWe believe that the presence of this subpopulation in BC patients might have an impact on the HER2+ patients´ response to antibody-therapy.