title: Neutrophil subset responses in infants with severe viral respiratory infection.
abstract: Neutrophils are the predominant inflammatory cells recruited to the respiratory tract as part of the innate immune response to viral infections. Recent reports indicate the existence of distinct functional neutrophil subsets in the circulatory compartment of adults, following severe inflammatory conditions. Here, we evaluated the occurrence of neutrophil subsets in blood and broncho-alveolar lavage fluid during severe viral respiratory infection in infants based on CD16/CD62L expression. We show that during the course of severe respiratory infection infants may develop four heterogeneous neutrophil subsets in blood (mature, immature, progenitor, and suppressive neutrophils), each with distinct activation states. However, while isolated viral respiratory infection was characterized by a relative absence of suppressive neutrophils in both blood and lungs, only patients with bacterial co-infection were shown to produce suppressive neutrophils. These data suggest the occurrence of distinct and unique neutrophil subset responses during severe viral and (secondary) bacterial respiratory infection in infants.
authors.affiliation: Pediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital Academic Medical Centre, Amsterdam, The Netherlands. Electronic address: b.cortjens@amc.nl.
authors.forename: Bart
authors.initials: B
authors.lastname: Cortjens
authors.affiliation: Pediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Ingelse
authors.affiliation: Pediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Job C
authors.initials: JC
authors.lastname: Calis
authors.affiliation: Laboratory of Experimental Intensive Care and Anesthesia, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Vlaar
authors.affiliation: Department of Respiratory Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Leo
authors.initials: L
authors.lastname: Koenderman
authors.affiliation: Pediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Reinout A
authors.initials: RA
authors.lastname: Bem
authors.affiliation: Pediatric Intensive Care Unit, Academic Medical Centre, Emma Children's Hospital Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Job B
authors.initials: JB
authors.lastname: van Woensel
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology / Q000382:microbiology; D060085:Coinfection / Q000276:immunology / Q000382:microbiology / Q000821:virology; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008168:Lung / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D008297:Male; D009504:Neutrophils / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D012141:Respiratory Tract Infections / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D014777:Virus Diseases / Q000276:immunology* / Q000821:virology
keywords: Inflammation; Innate immunity; RSV; Respiratory syncytial virus