Kinetic studies on lymphocytes labelled with indium 111-oxine in patients with chronic lymphocytic leukaemia.

The kinetics of 111Indium-oxine-labelled autologous blood lymphocytes were studied in normal subjects and 10 patients with chronic lymphocytic leukaemia (CLL). In both normal and leukaemic subjects, intravascular survival of lymphocytes was characterized by two exponential decreases, the first being a rapid one and the second slow phase. T 1/2 of the second phase for normal T lymphocytes (52.0 +/- 3.2 h: mean +/- SEM) was longer than that for B lymphocytes (31.6 +/- 2.8 h). T 1/2 of the second phase in patients with CLL was 15.1 to 192.6 h, which correlated well with the clinical stage of CLL by the Rai classification. Body surface scanning revealed prominent splenic accumulation of labelled cells in normal individuals and patients with CLL. Lymph node visualization was recognized in all patients with T-cell CLL; however, there was no visualization in 8 of the 9 patients with B-cell CLL. The longer survival time and splenic and lymph node visualization suggest that an expansion of the extravascular lymphocyte pool may be important in the pathophysiology of CLL.