Studies of bronchoalveolar lavage fluid in exogenous allergic alveolitis

: Current research results on the bronchoalveolar lavage (BAL) fluid of patients with extrinsic allergic alveolitis (EAA) are represented in a survey. The method of BAL, the preparation of the BAL-fluid, the differential cell count, the differentiation of lymphocytes, the determination of metabolic activity of alveolar macrophages and of the humoral components are described. The elevated total cell number, the relative and absolute increase of the total and T-lymphocyte number, the raised total protein content and the increased activity of T-lymphocytes and macrophages are characteristic features of the BAL-fluid in EAA. The possible significance of these changes for the pathogenesis of EAA and the problem of the so-called sensitized asymptomatics are discussed.