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Journal of Immunology Research
Volume 2018, Article ID 2438598, 18 pages
Research Article

Natural Killer Cells from Malignant Pleural Effusion Are Endowed with a Decidual-Like Proangiogenic Polarization

1Vascular Biology and Angiogenesis Laboratory, Scientific and Technology Pole, IRCCS MultiMedica, Milano, Italy
2Immunology and General Pathology Laboratory, Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
3Department of Medicine and Surgery, University of Insubria, Varese, Italy

Correspondence should be addressed to Douglas M. Noonan; ti.airbusninu@nanoon.salguod

Received 6 October 2017; Accepted 19 December 2017; Published 29 March 2018

Academic Editor: Cinzia Fionda

Copyright © 2018 Annalisa Bosi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Natural killer (NK) cells are crucial in tumor recognition and eradication, but their activity is impaired in cancer patients, becoming poorly cytotoxic. A particular type of NK cells, from the decidua, has low cytotoxicity and shows proangiogenic functions. We investigated whether NK cells from peripheral blood (PB) and pleural effusions of patients develop decidual-like NK phenotype and whether exposure to IL-2 can restore their killing ability in the presence of pleural fluids. NK cells from pleural effusion of patients with inflammatory conditions (iPE, n = 18), primary tumor (ptPE, n = 18), and metastatic tumor (tmPE, n = 27) acquired the CD56brightCD16 phenotype. NK cells from both ptPE and tmPE showed increased expression for the CD49a and CD69 decidual-like (dNK) markers and decreased levels of the CD57 maturation marker. NK from all the PE analyzed showed impaired degranulation capability and reduced perforin release. PE-NK cells efficiently responded to IL-2 stimulation in vitro. Addition of TGFβ or cell-free pleural fluid to IL-2 in the culture medium abrogated NK cell CD107a and IFNγ expression even in healthy donors (n = 14) NK. We found that tmPE-NK cells produce VEGF and support the formation of capillary-like structures in endothelial cells. Our results suggest that the PE tumor microenvironment can shape NK cell polarization towards a low cytotoxic, decidual-like, highly proangiogenic phenotype and that IL-2 treatment is not sufficient to limit this process.