Granulocyte margination in the human lung and its response to strenuous exercise

1. It is widely believed that the lung is an important site of granulocyte margination and releases most of the granulocytes of the peripheral neutrophilia of exercise. 2. We measured granulocyte margination in the lung in terms of the lung total blood granulocyte pool and the lung circulating granulocyte pool in eight patients without inflammatory disease or evidence of lung pathology by comparing the regional gamma-camera lung count rate of 111In-labelled granulocytes with that of 111In-labelled erythrocytes. According to the respective 111In activities in peripheral blood samples taken between 5 and 40 min after granulocyte injection, the lung marginating granulocyte pool was 0.78 (SEM 0.045) of the lung total blood granulocyte pool or 4.6 (0.92) of the lung circulating granulocyte pool 5 min after injection, decreasing to plateau values of 0.57 (0.053) and 1.53 (0.28) from 20 min after injection. This compared with corresponding whole-body ratios of about 0.6 and 1.5, respectively. 3. After 4 min of maximal exercise in four normal subjects given 111In-labelled granulocytes 60 min before exercise, the 111In-labelled granulocyte count rate over the lung increased to 1.23 (0.05) of the pre-exercise value with a time course that was essentially identical with the time course of the peripheral native neutrophilia. The spleen 111In signal decreased with the same time course, reaching a minimum of 0.63 (0.05) of the pre-exercise level at 5-10 min after the end of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)