title: A paradoxical role for myeloid-derived suppressor cells in sepsis and trauma.
abstract: Myeloid-derived suppressor cells (MDSCs) are a heterogenous population of immature myeloid cells whose numbers dramatically increase in chronic and acute inflammatory diseases, including cancer, autoimmune disease, trauma, burns and sepsis. Studied originally in cancer, these cells are potently immunosuppressive, particularly in their ability to suppress antigen-specific CD8(+) and CD4(+) T-cell activation through multiple mechanisms, including depletion of extracellular arginine, nitrosylation of regulatory proteins, and secretion of interleukin 10, prostaglandins and other immunosuppressive mediators. However, additional properties of these cells, including increased reactive oxygen species and inflammatory cytokine production, as well as their universal expansion in nearly all inflammatory conditions, suggest that MDSCs may be more of a normal component of the inflammatory response ("emergency myelopoiesis") than simply a pathological response to a growing tumor. Recent evocative data even suggest that the expansion of MDSCs in acute inflammatory processes, such as burns and sepsis, plays a beneficial role in the host by increasing immune surveillance and innate immune responses. Although clinical efforts are currently underway to suppress MDSC numbers and function in cancer to improve antineoplastic responses, such approaches may not be desirable or beneficial in other clinical conditions in which immune surveillance and antimicrobial activities are required.
authors.affiliation: Department of Surgery, University of Florida College of Medicine, Gainesville, Florida 32610-0286, United States of America.
authors.forename: Alex G
authors.initials: AG
authors.lastname: Cuenca
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Delano
authors.forename: Kindra M
authors.initials: KM
authors.lastname: Kelly-Scumpia
authors.forename: Claudia
authors.initials: C
authors.lastname: Moreno
authors.forename: Philip O
authors.initials: PO
authors.lastname: Scumpia
authors.forename: Drake M
authors.initials: DM
authors.lastname: Laface
authors.forename: Paul G
authors.initials: PG
authors.lastname: Heyworth
authors.forename: Philip A
authors.initials: PA
authors.lastname: Efron
authors.forename: Lyle L
authors.initials: LL
authors.lastname: Moldawer
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D049109:Cell Proliferation; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D018448:Models, Immunological; D022423:Myeloid Cells / Q000276:immunology*; D018805:Sepsis / Q000276:immunology*; D014947:Wounds and Injuries / Q000276:immunology*