title: Diagnosis of viral infections using myxovirus resistance protein A (MxA).
abstract: BACKGROUND
  Myxoma resistance protein 1 (MxA) is induced during viral infections. MxA testing could be helpful to differentiate between viral and bacterial infections.
  
  
  METHODS
  A prospective multicenter cohort study was performed in pediatric emergency departments. MxA blood values were measured in children with confirmed viral or bacterial infections, uninfected controls, and infections of unknown origin. First patients were used to determine MxA threshold for viral infection. The diagnostic performance of MxA was determined by using receiver operating characteristic (ROC) analysis. Sensitivities (Se), specificities (Sp), and positive and negative likelihood ratios (LR+, LR-) were calculated.
  
  
  RESULTS
  The study included 553 children; 44 uninfected controls and 77 confirmed viral infections (mainly respiratory syncytial virus and rotavirus) were used to determine an MxA threshold at 200 ng/mL. In the 193 other patients with confirmed infections and uninfected controls (validation group), MxA was significantly higher in patients with viral than in those with bacterial infections and uninfected controls (P < .0001). The area under the ROC curve (AUC) were 0.98, with 96.4% Se and 85.4% Sp, for differentiating uninfected from virus-infected patients and 0.89, with 96.4% Se and 66.7% Sp, for differentiating bacterial and viral infections. MxA levels were significantly higher in patients with clinically diagnosed viral versus clinically diagnosed bacterial infections (P < .001). Some patients with Streptococcus pneumonia infections had high MxA levels. Additional studies are required to elucidate whether this was due to undiagnosed viral coinfections.
  
  
  CONCLUSIONS
  MxA is viral infection marker in children, at least with RSV and rotavirus. MxA could improve the management of children with signs of infection.
authors: Université de Lille 2, Faculté de Médecine, Centre Hospitalier Régional Universitaire de Lille, Laboratoire de Virologie EA3610, Lille, France;
authors: Ilka
authors: I
authors: Engelmann
authors: Université de Lille 2, Faculté de Médecine, Centre Hospitalier Régional Universitaire de Lille, Laboratoire de Virologie EA3610, Lille, France;
authors: François
authors: F
authors: Dubos
authors: Université de Lille 2, Faculté de Médecine, Centre Hospitalier Régional Universitaire de Lille, Laboratoire de Virologie EA3610, Lille, France;
authors: Pierre-Emmanuel
authors: PE
authors: Lobert
authors: Université de Lille 2, Urgences pédiatriques et maladies infectieuses, Centre Hospitalier Régional Universitaire Lille and Université de Lille 2 et EA2694 Santé publique: épidémiologie et qualité des soins, Lille, France;
authors: Claire
authors: C
authors: Houssin
authors: Université de Lille 2, Urgences pédiatriques et maladies infectieuses, Centre Hospitalier Régional Universitaire Lille and Université de Lille 2 et EA2694 Santé publique: épidémiologie et qualité des soins, Lille, France;
authors: Vanessa
authors: V
authors: Degas
authors: Service de Pédiatrie, Centre Hospitalier de Lens, Lens, France; and.
authors: Anne
authors: A
authors: Sardet
authors: Institut Catholique de Lille, Laboratoire Hôpital St Philibert, Lomme Cedex, France.
authors: Anne
authors: A
authors: Decoster
authors: Université de Lille 2, Faculté de Médecine, Centre Hospitalier Régional Universitaire de Lille, Laboratoire de Virologie EA3610, Lille, France;
authors: Anny
authors: A
authors: Dewilde
authors: Université de Lille 2, Urgences pédiatriques et maladies infectieuses, Centre Hospitalier Régional Universitaire Lille and Université de Lille 2 et EA2694 Santé publique: épidémiologie et qualité des soins, Lille, France;
authors: Alain
authors: A
authors: Martinot
authors: Université de Lille 2, Faculté de Médecine, Centre Hospitalier Régional Universitaire de Lille, Laboratoire de Virologie EA3610, Lille, France; didier.hober@chru-lille.fr.
authors: Didier
authors: D
authors: Hober
mesh_terms: D000293:Adolescent; D001424:Bacterial Infections / Q000097:blood* / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005260:Female; D005602:France; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D064547:Myxovirus Resistance Proteins / Q000097:blood*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis; D012400:Rotavirus Infections / Q000175:diagnosis; D014777:Virus Diseases / Q000097:blood* / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D064547:Myxovirus Resistance Proteins
keywords: MxA; biomarker; children; myxoma resistance protein 1; virus