Purpose of review: Hypersensitivity pneumonitis is a group of immunologically mediated diseases caused by an abnormal response to a wide variety of inhaled antigens. Its pathogenesis is complex and involves many immunological concepts. This review discusses recent advances in our understanding of the pathogenesis of hypersensitivity pneumonitis.
Recent findings: Over the last 3 years, several studies on the pathogenesis of hypersensitivity pneumonitis have been published. New antigens have been identified. We now have a better understanding of the role of inflammatory cells and mediators, and promoting and protective factors have been suggested.
Summary: Most of the mechanisms involved in the pathogenesis of hypersensitivity pneumonitis remain incompletely understood. Current and future findings will not only help our understanding of the disease and its prevention, but also improve its treatment.