Increased recovery of neutrophils, macrophages and lymphocytes following repeated lavage of sheep lung in vivo.

The effect of bronchopulmonary lavage of adult sheep with sterile saline on the number and type of cells recovered in subsequent lavages was studied. We found that neutrophils increased from negligible numbers to 66 +/- 29 X 10(6) per lung (p less than 0.05), one day following the initial lavage. Alveolar macrophages also increased, from 39 +/- 4 to 69 +/- 13 X 10(6) per lung (p less than 0.005) 4 days following the initial lavage. Lymphocytes increased from 14 +/- 2 to 56 +/- 17 X 10(6) per lung (p less than 0.05) after 1 day, and remained elevated through 4 days. Numbers of all three cell types returned to baseline by the 7th day. No changes in numbers of neutrophils or macrophages were noted when the contralateral lung was lavaged 1 or 3 days after the original lavage. Cell types in peripheral blood were unchanged 24 hours after the initial lavage. We conclude that factors released in response to lavage act locally to produce increases in neutrophils, lymphocytes and macrophages which return to normal after 7 days.