title: Clinical implications of initial peripheral eosinophilia in acute eosinophilic pneumonia.
abstract: OBJECTIVE
  The initial peripheral eosinophil count (PEC) is rarely elevated but tends to increase during the clinical course of acute eosinophilic pneumonia (AEP). We evaluated whether initial peripheral eosinophilia is an indicator of mild disease in patients with AEP.
  
  
  METHODS
  We retrospectively examined associations between initial peripheral absolute eosinophil count, inflammatory markers and clinical characteristics in 85 patients with AEP.
  
  
  RESULTS
  Of 85 patients, 24 (28%) had initial peripheral eosinophilia (>500/μL). Initial peripheral absolute eosinophil count was inversely correlated to white blood cell (WBC) count (ρ = -0.386, P < 0.001), neutrophil percentage (ρ = -0.645, P < 0.001) and C-reactive protein (CRP; ρ = -0.495, P < 0.001). During treatment, peripheral absolute eosinophil counts increased, while inflammatory markers (WBC, neutrophil percentage, and CRP) decreased. Patients with initial peripheral eosinophilia had a longer duration from onset of symptoms to admission (P = 0.006), had lower WBC counts, neutrophil percentages and CRP values (all P < 0.001), and higher oxygen saturation (P = 0.004) than patients with normal peripheral eosinophil counts. Oxygen requirements (P = 0.013), duration of oxygen administration (P = 0.028) and intensive care unit admission rates (P = 0.003) were lower in patients with initial peripheral eosinophilia. All patients survived and recovered fully after corticosteroid or conservative treatment.
  
  
  CONCLUSIONS
  Initial PEC may be related to a milder disease status on admission, compared with normal PEC in patients with AEP. This may help to stratify disease severity in AEP.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, The Armed Forces Capital Hospital, Seong-nam, Republic of Korea.
authors.forename: Byung Woo
authors.initials: BW
authors.lastname: Jhun
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Kang
authors.initials: K
authors.lastname: Kim
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Lee
mesh_terms: D000208:Acute Disease; D002097:C-Reactive Protein / Q000378:metabolism; D004804:Eosinophils; D005260:Female; D006760:Hospitalization; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D011657:Pulmonary Eosinophilia / Q000097:blood* / Q000175:diagnosis / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D002097:C-Reactive Protein
keywords: acute eosinophilic pneumonia; disease severity; inflammatory marker; peripheral eosinophilia