Cytophilic antibodies in bronchopulmonary aspergilloma and cryptogenic pulmonary eosinophilia.

The immunoglobulin class and subclass of cytophilic antibodies have been studied using peripheral leucocytes from twenty-two patients with allergic bronchopulmonary aspergillosis, aspergilloma and cryptogenic pulmonary eosinophilia. In patients with allergic bronchopulmonary aspergillosis, significantly increased histamine liberation occurred following challenge of their leucocytes with antisera to IgE, IgG2, IgG3 and IgG4 as well as with Aspergillus fumigatus antigen. The results were considerably modified if the patient was receiving corticosteroids at the time of the test. The presence of IgG2-specific antibody to A. fumigatus in the serum of one patient, capable of sensitizing donor leucocytes, was demonstrated in passive sensitization experiments. In two patients with uncomplicated aspergillomas no evidence of cytophilic antibody to any class was found although large amounts of precipitating IgG antibody was present in the serum. Two patients with aspergilloma and systemic symptoms of weight loss and fatigue (which have been interpreted by others as 'hypersensitivity' responses) had increased amounts of cytophilic antibody similar to those with allergic bronchopulmonary aspergillosis. Six patients with cryptogenic pulmonary eosinophilia were also studied. No evidence of specific antibody to A. fumigatus was found but, as a group, significantly increased histamine liberation using antisera to IgG2 was demonstrated. Individual patients also showed evidence of other classes of cytophilic antibody, one having IgE, three IgG3 and two IgG4. The relationship between heat-stable short-term sensitizing antibody (IgG STS) inducing immediate skin responses and the pattern of cytophilic antibodies found in our patients with bronchopulmonary aspergillosis having dual (immediate and late reactions) is discussed. Clinically these tests are of diagnostic value and they may be helpful in assessing symptomatic patients with aspergillomas for corticosteroid treatment.