Farmer's lung
Encyclopedia
Farmer's lung is a hypersensitivity pneumonitis
induced by the inhalation of biologic dusts coming from hay
dust or mould spores or other agricultural products. It results in a type III hypersensitivity
inflammatory response and can progress to become a chronic condition which is considered potentially dangerous. Whilst inhaled allergens often provoke the creation of IgE
antibodies that circulate in the bloodstream, these types of immune response are most often initiated by exposure to thermophilic actinomycetes (most commonly Micropolyspora faeni and less commonly Saccharopolyspora rectivirgula
), which generates IgG-type antibodies. Following a subsequent exposure, IgG antibodies combine with the inhaled allergen
to form immune complex
es in the walls of the alveoli in the lung
s. This causes fluid, protein and cells to accumulate in the alveolar wall which slows blood-gas interchange and compromises the function of the lung.
Hypersensitivity pneumonitis
Hypersensitivity pneumonitis is an inflammation of the alveoli within the lung caused by hypersensitivity to inhaled organic dusts. Sufferers are commonly exposed to the dust by their occupation or hobbies.-Pathophysiology:Hypersensitivity pneumonitis involves inhalation of an antigen...
induced by the inhalation of biologic dusts coming from hay
Hay
Hay is grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing livestock such as cattle, horses, goats, and sheep. Hay is also fed to pets such as rabbits and guinea pigs...
dust or mould spores or other agricultural products. It results in a type III hypersensitivity
Type III hypersensitivity
Type III hypersensitivity occurs when antigens and antibodies are present in roughly equal amounts, causing extensive cross-linking.-Presentation:...
inflammatory response and can progress to become a chronic condition which is considered potentially dangerous. Whilst inhaled allergens often provoke the creation of IgE
IGE
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antibodies that circulate in the bloodstream, these types of immune response are most often initiated by exposure to thermophilic actinomycetes (most commonly Micropolyspora faeni and less commonly Saccharopolyspora rectivirgula
Saccharopolyspora rectivirgula
Saccharopolyspora rectivirgula is a species of bacteria. It is a Gram-positive rod. It was formerly known as Micropolyspora faeni.Inhalation of the bacteria can cause the disease farmer's lung, a type of hypersensitivity pneumonitis. Handling hay bales increases exposure to the bacteria and...
), which generates IgG-type antibodies. Following a subsequent exposure, IgG antibodies combine with the inhaled allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....
to form immune complex
Immune complex
An immune complex is formed from the integral binding of an antibody to a soluble antigen. The bound antigen acting as a specific epitope, bound to an antibody is referred to as a singular immune complex....
es in the walls of the alveoli in the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s. This causes fluid, protein and cells to accumulate in the alveolar wall which slows blood-gas interchange and compromises the function of the lung.