Leucocyte behaviour in controlled ischaemia of the calves.

Whole blood filterability and leucocyte behaviour (number, activation, and subfraction filterability rates) were monitored at the earliest stage of peripheral ischaemia in 18 patients with stage II peripheral occlusive arterial disease (PAOD) and 20 matched controls. A model of controlled ischaemia, using exercise to stress leg circulation, was set up and blood samples were taken before exercise, at the onset of calf pain, and at recovery from peak exercise. Leucocytes were counted, separated into their subfractions on a Ficoll-Hypaque density gradient and by adhesion to Petri dishes, and filtered in buffer (like the whole blood suspensions) through 5 microns pore diameter Nucleopore filters. Unfractionated white cells, separated under gravity, with pseudopodia or cytoplasmic irregularities were regarded as activated. The whole blood filterability rate was significantly increased at the onset of calf pain and was associated with significant increases in the number of leucocytes and in the filterability rate of the monocyte subfraction, the latter persisting throughout the recovery period. No significant changes were observed in the other variables monitored, showing that impairments in white cell rheology may be associated with ischaemia.