title: Aetiology of febrile pharyngitis in children: Potential of myxovirus resistance protein A (MxA) as a biomarker of viral infection.
abstract: Besides group A streptococcus (GAS), microbial causes of pharyngitis in children are not well known. We aimed to document the viral and bacterial aetiology of pharyngitis and to assess the pathogenic role of viruses by determining the myxovirus resistance protein A (MxA) in the blood as a marker of interferon response.
  
  
  
  In this prospective observational study, throat swabs and blood samples were collected from children (age 1-16 years) presenting to the emergency department with febrile pharyngitis. Microbial cause was sought by bacterial culture, polymerase chain reaction, and serology. Blood MxA level was determined.
  
  
  
  A potential pathogen was detected in 88% of 83 patients: GAS alone in 10%, GAS and viruses in 13%, group C or G streptococci alone in 2% and together with viruses in 3%, and viruses alone in 59% of cases. Enteroviruses, rhinoviruses, and adenoviruses were the most frequently detected viruses. Blood MxA levels were higher in children with viral (880 [245-1250] μg/L; median [IQR]) or concomitant GAS-viral (340 [150-710] μg/L) than in those with sole GAS (105 [80-160] μg/L) infections.
  
  
  
  Detection of respiratory viruses simultaneously with elevated blood MxA levels supports the causative role of viruses in the majority of children with pharyngitis.
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland; Department of Emergency Services, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: lauri.ivaska@utu.fi.
authors.forename: Lauri
authors.initials: L
authors.lastname: Ivaska
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland; Department of Emergency Services, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: jukani@utu.fi.
authors.forename: Jussi
authors.initials: J
authors.lastname: Niemelä
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland; Immunogenetics Laboratory, University of Turku, Turku, Finland. Electronic address: nojoaa@utu.fi.
authors.forename: Johanna
authors.initials: J
authors.lastname: Lempainen
authors.affiliation: Department of Clinical Virology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: riikka.osterback@utu.fi.
authors.forename: Riikka
authors.initials: R
authors.lastname: Österback
authors.affiliation: Department of Clinical Virology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: mwaris@utu.fi.
authors.forename: Matti
authors.initials: M
authors.lastname: Waris
authors.affiliation: Department of Clinical Virology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: tyvuori@utu.fi.
authors.forename: Tytti
authors.initials: T
authors.lastname: Vuorinen
authors.affiliation: Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland; Department of Clinical Microbiology and Immunology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: jukhyt@utu.fi.
authors.forename: Jukka
authors.initials: J
authors.lastname: Hytönen
authors.affiliation: Department of Clinical Microbiology and Immunology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: Kaisu.Rantakokko-Jalava@tyks.fi.
authors.forename: Kaisu
authors.initials: K
authors.lastname: Rantakokko-Jalava
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: vilpel@utu.fi.
authors.forename: Ville
authors.initials: V
authors.lastname: Peltola
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005334:Fever; D006801:Humans; D007223:Infant; D007372:Interferons / Q000276:immunology; D008297:Male; D064547:Myxovirus Resistance Proteins / Q000097:blood* / Q000302:isolation & purification; D010612:Pharyngitis / Q000175:diagnosis* / Q000209:etiology / Q000382:microbiology / Q000821:virology*; D010614:Pharynx / Q000382:microbiology / Q000821:virology; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012698:Serologic Tests; D013290:Streptococcal Infections / Q000175:diagnosis / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000302:isolation & purification; D014777:Virus Diseases / Q000175:diagnosis* / Q000821:virology; D014780:Viruses / Q000302:isolation & purification
chemical_list: D015415:Biomarkers; C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins; D007372:Interferons
keywords: GAS; Group A streptococcus; MxA; Myxovirus resistance protein A; Pharyngitis; Viral aetiology