title: Increased lymphoid MxA expression in acute asthma exacerbation in children.
abstract: BACKGROUND
  Although the association between acute asthma exacerbation and viral infection has been well documented, virus identification rates vary. It has recently been reported that the expression of MxA protein in lymphocytes, inducible by type I interferons, can serve as a sensitive marker for viral infection in the host. The objective was to determine the contribution of viral infection to precipitation of asthma attacks in children.
  
  
  METHODS
  We studied 186 asthmatic children, aged 0-12 years, over a 1-year period to evaluate MxA protein levels in peripheral blood lymphocytes by using a flow cytometric analysis in whole blood.
  
  
  RESULTS
  Of all the subjects, 80 (47%) exhibited significantly elevated levels of MxA expression in lymphocytes, presumably indicating the states of viral infection. The association of viral infections with acute asthma exacerbation seemed to be marked in younger children: enhanced MxA expression was seen in 73.3% of infants (aged 0-1 year), 49.5% of toddlers (aged 2-5 years), and 26% of schoolchildren (aged 6-12 years). Seasonal changes in the frequency of viral infection associated with deterioration were also observed.
  
  
  CONCLUSIONS
  Flow cytometric assay of MxA protein expression in whole blood appears to be an easy and useful method to evaluate viral infections in acute asthma exacerbation.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Itazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Adachi
authors.forename: H
authors.initials: H
authors.lastname: Imamura
authors.forename: Y
authors.initials: Y
authors.lastname: Okabe
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Onoue
authors.forename: Y S
authors.initials: YS
authors.lastname: Adachi
authors.forename: T
authors.initials: T
authors.lastname: Miyawaki
authors.forename: G
authors.initials: G
authors.lastname: Murakami
mesh_terms: D000208:Acute Disease; D000367:Age Factors; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology*; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D005453:Fluorescence; D005500:Follow-Up Studies; D019204:GTP-Binding Proteins; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D064547:Myxovirus Resistance Proteins; D014176:Protein Biosynthesis; D012621:Seasons
chemical_list: C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins; D019204:GTP-Binding Proteins