Abstract

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is an immunologically mediated granulomatous, inflammatory disease of the lungs caused by repeated inhalation of various antigens. HP may occur in acute, subacute, or chronic forms. Chronic HP may be progressive, irreversible, and evolve to fibrotic interstitial lung disease. The diagnosis of HP can be made from a combination of clinical, laboratory, radiologic, and pathologic findings. A careful environmental and occupational history and establishment of exposure to a known inciting antigen are key factors in making the diagnosis of HP. Serum precipitating antibodies, bronchoalveolar lavage, and lung biopsy may be helpful in making the diagnosis. The pathology of HP is characterized by interstitial lymphocytic infiltration, poorlyformed noncaseating granulomas, cellular bronchiolitis, and fibrosis. In the pathogenesis of HP, recent studies showed that both type III and type IV hypersensitivity reactions are involved and are mediated by immune complexes and Th1 T cells, respectively. IFN-γ is essential for the development of HP, and IL-10 appears to modulate the severity of the disease. TNF-α and TGF-β have been implicated in development of the pulmonary fibrosis that is seen in chronic HP. Avoidance of organic antigen exposure is the most important factor for the management of HP. There is often an apparent beneficial response to corticosteroids in the cases of severe acute and subacute HP, and for chronic HP that is severe or progressive.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.