IgA2-alveolitis and eosinophilic pneumonia--a possibly virus-triggered allergy.

A case of severe therapy-resistant asthma in a young girl with a duration of two years prior to death is reported. At autopsy antibodies of the IgA2-subtype were demonstrated in the lungs on the alveolar basement membranes. We were able to demonstrate intracellular virus-like structures by electron microscopy; this virus infection is taken to be the cause of antibody production. Following antigen-antibody reaction a non-complement-mediated eosinophilic pneumonia with numerous macrophages developed. This inflammatory reaction showed the injurious effect of eosinophilic granulocytes causing fibrinoid necrosis; this is confirmed by the pronounced depletion of the Charcot-Leyden-granules, equivalent to the release of the major basic protein and the Charcot-Leyden crystal protein. Death was caused by IgA2 deposition in the myocardial vessels with consequent eosinophilic myocarditis.