Flow-FISH analysis of PBL and T lymphocytes from a patient with CML.

Nucleated cells after lysis of red blood cells (A-C) as well as cultured T lymphocytes (D-E) were analyzed following hybridization with or without FITC-(C₃TA₂)₃ PNA (respectively dark gray and light gray histograms in C and F). The cells were gated on region 1 (R1) on the basis of propidium iodide (PI) fluorescence and forward light scatter (FSC) as is shown in A and D. An additional region 2 (R2) was selected within R1 from FSC versus side scatter (SCC) dot plot histograms as is shown in B and E. Note that the telomere fluorescence signal of lymphocytes (F, dark gray) is almost 2 times higher and more heterogeneous than that of the total blood leukocytes (C, dark gray) reflecting longer telomere length and a more diverse replicative history.52 54