Results on telomere length analysis. (A) Age-dependent telomere length percentiles (1%, 50%, and 99%) of lymphocytes based on telomere length measurements from 400 healthy persons.18 The age-related telomere length values of the male and female donors and recipients are represented for each donor/recipient pair. (B) The mean ± SD of telomere length (in kilobase pairs) for the diverse subsets of leukocytes from the 44 donors (blue) and recipients (red) is shown. (C-E) Factors influencing telomere length: box plots for the telomere length difference in kilobytes (telomere length value of the donor minus that of the recipient) of granulocytes and lymphocytes are shown. A greater value indicates a greater telomere length difference. (C) Telomere length difference in lymphocytes (P = .013) and granulocytes (P = .022) of recipients with or without chronic GVHD. (D) Telomere length difference in lymphocytes (P = .017) and granulocytes (P = .024) of recipients with a female or male donor. (E) Telomere length differences in lymphocytes (P = .025) and granulocytes (P = .024) of recipients with a male or female donor and with or without chronic GVHD and a male or female donor. (F-G) Simplified hypothetical model of telomere shortening after HSCT. The decrease in telomere length over a period of years after transplantation is shown. The light blue area indicates the expected range of telomere length, and the yellow area indicates where telomere length becomes critically short. The broken lines indicate the telomere length decrease. (F) Patient A, who received donor cells with longer telomeres, and patient B, who received donor cells with shorter telomeres. (G) Patient C, who experienced chronic GVHD, and patient D, who experienced chronic GVHD and had a female donor. Note the different time points at which the broken line of the telomere decline crosses with the telomere senescence checkpoint line (horizontal light brown line).