MSC-mediated modulation of NK-cell phenotype. Expression of activating NK receptors on the surface of IL-2–activated NK cells cultured for 6 days alone (▭) or in the presence of MSCs (). Results are represented as mean plus or minus SD of MRFIs (“Monoclonal antibodies and cytofluorimetric analysis”) obtained from 10 independent experiments. **P < .01; ***P < .001.