Immunologic response to Faenia rectivirgula (Micropolyspora faeni) in a dairy farm family

In the present study, cellular and humoral responses to Faenia rectivirgula antigens were evaluated in seven subjects, members of a family who lived and worked on a dairy farm.Four subjects had clinical features of hypersensitivity pneumonitis after exposure to nzotdy hay.The other three subjects had no clinical disease in spite of similar exposure.Although serum precipitins were found in most subjects, a biotin-avidin-linked immunosorbent assay revealed high levels of F. rectivirgula-specific antibodies only in the symptomatic subjects.In addition, numerous precipitin arcs were present in the sera of the symptomatic but not the asymptomatic subjects by antigen-antibody crossed immunoelectrophoresis.No clear distinction between symptomatic and asymptomatic subjects could be made on the basis of lymphocyte phenotype studies, and antigen-induced lymphocyte transformation was not detected in any subjects.The results indicate that F. rectivirgula-specific antibody levels as detected by biotin-avidin-linked immunosorbent assay and by the presence of precipitin arcs in crossed immunoelectrophoresis may difSerentiate symptomatic and asymptomatic farmers.(J ALLERGY &IN hiMUNOL 1988;82:190-5.)Farmer's lung disease is an occupational disease caused by the inhalation of antigen-laden dust, primarily from moldy hay.'The organisms associated with the moldy hay in these cases are predominantly thermophilic actinomycetes, including Faeniu recti- virgula (Micropolyspora faeni), Thermoactinomyces candidus, Thermoactinomyces vulgaris, and Saccharomonosporu viridis.'-' Several fungi, including Aspergillus fimigatus, have also been frequently isolated from moldy hay and have been implicated in this disease.',5-7 Patients with Farmer's lung disease invaribly demonstrate high levels of circulating antibodies to specific antigens.',* Cellular-immune responses in these patients have not been well studied, and the findings of the limited number of studies present conflicting results9-13This study is an environmental and immunologicFrom the Research Service, Clement J.