[Simultaneous illness in siblings with exogenous allergic alveolitis of the farmer's lung type--report of a 3-year course, familial sensitization and HLA markers].

Two sisters (6 and 8 years old) fell ill with coughing, fever and dyspnea after playing in the rotten straw in the barn of their parents' farm. Within 2 weeks symptoms changed to the insidious form of Exogen Allergic Alveolitis. In the broad spectrum of antibodies detected, the Thermophile Actinomycetes were probably the relevant antigens. In spite of efforts to avoid contact with the antigens, there was a relapse of the disease, the most probable sources of the antigens being a mattress in the bed-room and a fodderroom. Since consequent avoidance of antigens is practiced, no signs of relapse have been seen. The other three members of the family were exposed too. The mother and the youngest daughter showed neither symptoms nor specific antibodies. The father turned out to be sensibilitized too. By more attentive self-observation he discovered signs of illness. The distribution of the HLA-markers in the family was not concordant with the pattern of disease nor of antibodies. Some HLA-markers have been described as being associated with Exogen Allergic Alveolitis. Among the markers of our family there are none of these.