title: High-Sensitivity C-Reactive Protein Can Reflect Small Airway Obstruction in Childhood Asthma.
abstract: OBJECTIVE
  High-sensitivity assays enabled the identification of C-reactive protein (hs-CRP) at levels that were previously undetectable. We aimed to determine if hs-CRP could reflect airway inflammation in children, by comparing hs-CRP with spirometry and impulse oscillometry (IOS) parameters and symptomatic severities.
  
  
  METHODS
  A total of 276 asthmatic children who visited Severance Children's Hospital from 2012-2014 were enrolled. Serum hs-CRP and pulmonary function tests were performed on the same day. Patients were divided into hs-CRP positive and negative groups (cut-off value, 3.0 mg/L).
  
  
  RESULTS
  Of the 276 asthmatic children [median age 7.5 (5.9/10.1) years, 171 boys (62%)], 39 were hs-CRP positive and 237 were negative. Regarding spirometry parameters, we observed significant differences in maximum mid-expiratory flow, % predicted (FEF₂₅₋₇₅) (p=0.010) between hs-CRP positive and negative groups, and a negative correlation between FEF₂₅₋₇₅ and hs-CRP. There were significant differences in the reactance area (AX) (p=0.046), difference between resistance at 5 Hz and 20 Hz (R5-R20) (p=0.027), resistance at 5 Hz, % predicted (R5) (p=0.027), and reactance at 5 Hz, % predicted (X5) (p=0.041) between hs-CRP positive and negative groups. There were significant positive correlations between hs-CRP and R5 (r=0.163, p=0.008), and X5 (r=0.164, p=0.007). Spirometry and IOS parameters had more relevance in patients with higher blood neutrophil levels in comparison to hs-CRP.
  
  
  CONCLUSIONS
  Hs-CRP showed significant correlation with FEF₂₅₋₇₅, R5, and X5. It can reflect small airway obstruction in childhood asthma, and it is more prominent in neutrophil dominant inflammation.
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: A Ra
authors.initials: AR
authors.lastname: Ko
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea. yhkim@yuhs.ac.
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: In Suk
authors.initials: IS
authors.lastname: Sol
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seo Hee
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Severance Hospital, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyu-Earn
authors.initials: KE
authors.lastname: Kim
mesh_terms: D000402:Airway Obstruction / Q000175:diagnosis* / Q000209:etiology; D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D002097:C-Reactive Protein / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D009991:Oscillometry / Q000379:methods*; D012129:Respiratory Function Tests / Q000379:methods*; D012137:Respiratory System; D012680:Sensitivity and Specificity; D013147:Spirometry
chemical_list: D002097:C-Reactive Protein
keywords: High-sensitivity C-reactive protein; asthma; childhood