title: Immunoglobulin free light chains are increased in hypersensitivity pneumonitis and idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  Idiopathic pulmonary fibrosis (IPF), a devastating lung disorder of unknown aetiology, and chronic hypersensitivity pneumonitis (HP), a disease provoked by an immunopathologic reaction to inhaled antigens, are two common interstitial lung diseases with uncertain pathogenic mechanisms. Previously, we have shown in other upper and lower airway diseases that immunoglobulin free light chains (FLCs) are increased and may be involved in initiating a local inflammation. In this study we explored if such a mechanism may also apply to HP and IPF.
  
  
  METHODS
  In this study we examined the presence of FLC in serum and BAL fluid from 21 IPF and 22 HP patients and controls. IgG, IgE and tryptase concentrations were measured in BAL fluid only. The presence of FLCs, plasma cells, B cells and mast cells in lung tissue of 3 HP and 3 IPF patients and 1 control was analyzed using immunohistochemistry.
  
  
  RESULTS
  FLC concentrations in serum and BAL fluid were increased in IPF and HP patients as compared to control subjects. IgG concentrations were only increased in HP patients, whereas IgE concentrations were comparable to controls in both patient groups. FLC-positive cells, B cells, plasma cells, and large numbers of activated mast cells were all detected in the lungs of HP and IPF patients, not in control lung.
  
  
  CONCLUSIONS
  These results show that FLC concentrations are increased in serum and BAL fluid of IPF and HP patients and that FLCs are present within affected lung tissue. This suggests that FLCs may be involved in mediating pathology in both diseases.
authors: Division of Pharmacology and Pathophysiology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
authors: Tom
authors: T
authors: Groot Kormelink
authors: Annie
authors: A
authors: Pardo
authors: Karen
authors: K
authors: Knipping
authors: Ivette
authors: I
authors: Buendía-Roldán
authors: Carolina
authors: C
authors: García-de-Alba
authors: Bart R
authors: BR
authors: Blokhuis
authors: Moises
authors: M
authors: Selman
authors: Frank A
authors: FA
authors: Redegeld
mesh_terms: D000328:Adult; D000368:Aged; D000542:Alveolitis, Extrinsic Allergic / Q000097:blood / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D001992:Bronchoalveolar Lavage Fluid; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000097:blood / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D007073:Immunoglobulin E / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000097:blood / Q000378:metabolism*; D008168:Lung / Q000276:immunology / Q000503:physiopathology; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D008875:Middle Aged; D010950:Plasma Cells / Q000378:metabolism; D012129:Respiratory Function Tests; D053802:Tryptases / Q000378:metabolism
chemical_list: D007074:Immunoglobulin G; D007147:Immunoglobulin Light Chains; D007073:Immunoglobulin E; D053802:Tryptases