title: Variation of immunological response in methotrexate-induced pneumonitis.
abstract: OBJECTIVE
  To assess the variation of peripheral blood and bronchoalveolar lavage (BAL) inflammatory cell counts and lung biopsy findings with the degree of exposure to MTX therapy.
  
  
  METHODS
  Fifty-six (16 males; 40 females) reported cases of MTX-induced pneumonitis (MTX-P) on low-dose MTX (5-30 mg) were identified from a literature search and classified using Searles and McKendry's criteria. The median cumulative dose was 300 mg and this was used to categorize patients into low and high MTX-exposure groups and 6 months was used to divide patients into early- and late-onset MTX-P groups.
  
  
  RESULTS
  Neutrophil counts in the peripheral blood and BAL were significantly raised in the low MTX-exposure group compared with the high MTX-exposure group (P = 0.018 and 0.038, respectively). There were similar findings when early-onset was compared with late-onset group. Lymphocytes in BAL were significantly higher in the high MTX-exposure group compared with low-dose cumulative group (P = 0.007). There were 6 (11%) recorded deaths and all were in the low MTX-exposure group. Early-onset/low MTX-exposure groups had a high prevalence of lung fibrosis.
  
  
  CONCLUSIONS
  This is the first study to describe the variation of immunological responses in MTX-P with the degree of exposure to MTX. Our findings suggest that MTX-P can be divided into two groups: type 1 MTX-P that occurs early, predominated by neutrophils, lung fibrosis and has a high mortality; and type 2 MTX-P that occurs late, predominated by lymphocytes, has less lung fibrosis and low mortality.
authors.affiliation: Department of Rheumatology, Royal Liverpool University Hospitals, Prescot Street, Liverpool L78XP, UK. docbatsi@aol.com
authors.forename: B
authors.initials: B
authors.lastname: Chikura
authors.forename: N
authors.initials: N
authors.lastname: Sathi
authors.forename: S
authors.initials: S
authors.lastname: Lane
authors.forename: J K
authors.initials: JK
authors.lastname: Dawson
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016206:Databases, Bibliographic; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D008727:Methotrexate / Q000009:adverse effects*; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology; D011014:Pneumonia / Q000139:chemically induced* / Q000276:immunology* / Q000473:pathology; D018709:Statistics, Nonparametric
chemical_list: D018501:Antirheumatic Agents; D008727:Methotrexate