Bronchoalveolar lavage in extrinsic allergic alveolitis: effect of time elapsed since antigen exposure.

The aim of the present study was to investigate whether bronchoalveolar lavage (BAL) cell profile and immunoglobulin levels from patients with extrinsic allergic alveolitis (EAA) were related to the time elapsed between last antigen exposure and BAL. For this purpose, an analysis was performed of BAL fluid (BALF) obtained from 59 nonsmoking EAA patients at various time-points after termination of antigen exposure and BAL. BALF early after antigen provocation (group 1: < 24 h) contained high absolute and relative numbers of lymphocytes, neutrophils, eosinophils and mast cells, and a low relative number of alveolar macrophages. When obtained after recent antigen exposure (group 2: 2-7 days), BALF showed high numbers of lymphocytes, plasma cells and mast cells, and high levels of immunoglobulins M, G and A (IgM, IgG and IgA). In BAL obtained one week or more after the final antigen exposure, (Group 3: 8-30 days; Group 4: 1-12 months) the distribution of all constituents showed a tendency to return to normal values, with the exception of the lymphocytes. These results demonstrate that BAL cell profile and immunoglobulin levels in EAA are highly dependent on the time-point at which the material is obtained in relation to the last exposure to the causative antigen.