title: Lung biopsy-proved hypersensitivity pneumonitis without known offending antigen: characteristics and follow-up.
abstract: BACKGROUND
  Hypersensitivity pneumonitis (HP) without known offending antigen is hard to diagnose.
  
  
  OBJECTIVE
  The purpose of this study was to identify and analyze the clinical features of lung biopsy-proved HP.
  
  
  METHODS
  A retrospective cohort study was performed using a database from a 900-bed specialty hospital. Twenty-eight patients with the diagnosis of HP through lung biopsy were enrolled. Demographic data and clinical characteristics, radiologic characteristics, serologic and pulmonary function results, histopathologic changes, treatment and follow-up were analyzed.
  
  
  RESULTS
  Of all the patients, serum interleukin-1β, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), eosinophil cationic protein and immunoglobulin E (IgE) were increased in over 50% patients, but decreased significantly after corticosteroid therapy (P < 0.05). An initially reduced diffusion lung capacity for carbon monoxide was noted in 92.9% patients, while 39.3% patients had hypoxemia. Ground-glass opacities on the basis of interlobular septa thickening were observed in 71.4% cases. Histopathological findings demonstrated peribronchiolar lymphocytic infiltrates, poorly formed non-caseating granulomas fibrosis in all acute and subacute HP patients' lungs. Ninety-two percent of patients got improvement after corticosteroid therapy when assessed by computer tomography scans and pulmonary function tests.
  
  
  CONCLUSIONS
  For suspected HP patients who without known offending antigens, earlier diagnosed by lung biopsy and followed by corticosteroid therapy showed promising. It might prevent the disease progression to lung fibrosis.
authors.affiliation: Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Jin-Fu
authors.initials: JF
authors.lastname: Xu
authors.forename: Li
authors.initials: L
authors.lastname: Shen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Jie-Ming
authors.initials: JM
authors.lastname: Qu
authors.forename: Hui-Ping
authors.initials: HP
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D000542:Alveolitis, Extrinsic Allergic / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D001706:Biopsy; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D002248:Carbon Monoxide / Q000378:metabolism; D015331:Cohort Studies; D047150:Eosinophil Cationic Protein / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006099:Granuloma / Q000473:pathology; D006801:Humans; D000860:Hypoxia / Q000209:etiology; D007073:Immunoglobulin E / Q000097:blood; D053583:Interleukin-1beta / Q000097:blood; D008168:Lung / Q000473:pathology*; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use; D011658:Pulmonary Fibrosis / Q000473:pathology; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D005938:Glucocorticoids; D053583:Interleukin-1beta; D007073:Immunoglobulin E; D002248:Carbon Monoxide; D002097:C-Reactive Protein; D047150:Eosinophil Cationic Protein; D011241:Prednisone
keywords: diagnosis; follow-up; hypersensitivity pneumonitis; lung biopsy; offending antigen