Infusion of endotoxin elicits lymphopenia and a transient granulocytop
enia followed by granulocytosis in peripheral blood. The purpose of th
is study was to investigate which tissues the lymphocytes are redistri
buted to in response to endotoxaemia. Lymphocytes were isolated from t
he peripheral blood of 20 rabbits, labelled with Indium-111-tropolene
and reinjected intravenously into the rabbits. Ten rabbits received an
infusion of Escherichia coli endotoxin 2 mug/kg-1, while 10 rabbits r
eceived isotonic saline and served as a control group. The redistribut
ion of lymphocytes was imaged with a gamma camera, and calculated with
an interfaced computer before, and 2, 4 and 6 h after infusion of end
otoxin or saline. Interleukin-1beta and serum cortisol were measured.
Following endotoxaemia the lymphocytes in peripheral blood decreased f
rom 1.95 10(9)/1 to 0.83 6 h later. Interleukin-1beta and serum cortis
ol increased significantly. The radioactivity of labelled cells in the
spleen and in the heart and lungs decreased to 83.3% and 87.8% of ini
tial values respectively, 6 h after infusion of endotoxin. The radioac
tivity of the lymphatic tissue in and around the intestine increased t
o 128.8% of initial values. The results indicate that endotoxaemia ind
uces redistribution of lymphocytes from peripheral blood and spleen to
lymphatic tissue.