Energy transfer efficiency on lymphocytes of leukemia patients measured by fluorescence polarization

Measurements of fluorescence resonance energy transfer efficiency (E), via fluorescence polarization, have been applied to distinguish between chronic lymphocytic leukemia (CLL) patients and healthy persons. Capping of Concanavalin-A receptors is more pronounced in normal lymphocytes than in those of CLL patients. Membrane capping decreases the distance between donor and acceptor molecules embedded in the membrane (r), and thus increases the monitored energy transfer efficiency (E approximately 1/r6). Blood samples of 10 healthy subjects and 16 CLL patients were examined. In the healthy subjects, the mean E value for capped lymphocytes was 19 +/- 3, whereas in the CLL patients it was significantly lower (8 +/- 5) (P < 0.01).