Myeloid-derived suppressor cells: a double-edged sword?

P>Myeloid-derived suppressor cells are important cell population with an immunoregulatory potential in both adaptive and innate immunity. Their immunosuppressive activity is widely accepted. However, emerging evidence suggests that this heterogeneous cell population can be, under some circumstances, immunostimulatory rather than suppressive. This finding can shed a new light on antitumour immunity which is believed to be impaired in immunosuppressive environments.