Telomere length and telomerase activity of B-CLL cells in relation to patient survival and lymphocyte doubling time. (A) Kaplan-Meier plots of survival in 56 B-CLL patients stratified by median value of telomere length (2.91 kb). (B) Kaplan-Meier plots of survival in 42 B-CLL patients stratified by median value of telomerase activity (21.8 TPG U). (C) Scatter plot of telomere length in 57 patients stratified by differences in LDT. Note that patients with LDT less than 12 months exhibited significantly shorter telomeres (mean, 2.81 kb) compared with those with LDT of 12 months or more (mean, 3.88 kb; P < .01). (D) Scatter plot of telomerase activity in 43 patients stratified by differences in LDT. Note that patients with LDT less than 12 months exhibited significantly higher telomerase activity (mean, 40.3 TPG U) than those with LDT of 12 months or more (mean, 19.1 TPG U; P < .01).