Cell membrane fluidity in blast cells of children with acute leukaemia.

Plasma membrane fluidity has been investigated by determining steady-state fluorescence polarization (FP) of the apolar stain 1,6-diphenyl-1,3,5,-hexatriene in intact blast cells, separated from peripheral blood and bone marrow of children with various types of acute leukaemia. FP-values of blast cells taken before antileukaemic therapy were compared with FP-values of peripheral blood and bone marrow mononuclear cells separated from patients in complete remission as well as from control patients and from healthy volunteers. Moreover, fluorescence polarization measurements were also performed using blast cells of leukaemic patients on short-term single-drug prednisolone pretreatment. The results have shown that untreated blast cells have significantly lower FP-values than normal mononuclear cells of peripheral blood or bone marrow. No compartment difference has been observed within blast cells, while normal mononuclear cells from peripheral blood have significantly higher FP-values than bone marrow cells. FP-values of cells separated in remission or during prednisolone treatment do not differ from control values.