Features of bronchoalveolar lavage differentiating hypersensitivity pneumonitis and pulmonary sarcoidosis at time of initial presentation.

To evaluate the usefulness of bronchoalveolar lavage (BAL) as an aid in differentiating hypersensitivity pneumonitis (HP) and pulmonary sarcoidosis (S), we studied the cellular and protein components of BAL and pulmonary function tests (PFT) in 11 patients with acute HP and 23 patients with S at the time of initial presentation and compared the findings with those of normals. The only significant difference between the two groups of patients, on the basis of all the PFT performed, was an exercise-induced hypoxemia PaO2 = 75 +/- 4 torr) in patients with HP that, on average, was not found in patients with S (PaO2 = 88 +/- 3 torr) at the same 1.6 l min-1 O2 consumption. In patients with HP, the total cellular yield of BAL was, on average, 4 times that of patients with S and 6 times that of normals (p less than 0.01 for both). Macrophages, as % of total cells, were reduced in both groups of patients but increased in terms of cells ml-1. Lymphocytes in patients with HP averaged 61.4 +/- 6.5%, in patients with S, 32.6 +/- 4.2%, both values being significantly higher than normal (3.2 +/- 0.9%). However the percentages of lymphocytes in BAL did not clearly separate individual patients with HP from those with S.(ABSTRACT TRUNCATED AT 250 WORDS)