Pulmonary reactions to non-infective antigenic contaminants.

There are different categories of non-infectious antigenic contaminants capable of provoking pulmonary reactions: thermophilic actinomycetales, fungi, vegetable particles, protein antigens, arthropods, drugs; their identification is based on their isolation, culture, and the study of their biochemical composition. The pulmonary reactions depend on the size and number of antigenic particles inhaled and by the underlying background. The immunological mechanisms brought into play a complex Arthus's phenomenon: in addition to the IgGs, the IgEs and the different factors of complement intervene; the recent acquisitions of immunomorphology enable better comprehension of the histogenesis of the pulmonary granuloma. The diagnosis of extrinsic allergic alveolitis is founded on well defined criteria of clinical, radiological, respiratory functional, immunological and histophthological order. These conditions are met with in agricultural, industrial and urban environments or are related to iatrogenic diseases. Many problems still remain obscure with regards to the pathogenesis and integration within the framework of immunological pneumonia of various conditions, and especially certain sarcoidosis.