Telomere length changes in patients undergoing hematopoietic stem cell transplantation

Telomere length indicates the replicative history of cells, serving as a mo lecular measure of the replicative potential remaining in cells. To investi gate telomere length changes in hematopoietic stem cells, patients undergoi ng hematopoietic stem cell transplantation (HSCT) mere evaluated, Fifteen p atients after allogeneic bone marrow transplantation (allo-BMT group), seve n patients after autologous peripheral blood stem cell transplantation (aut o-PBSCT group), and 39 healthy controls mere studied. Telomere length was m easured in peripheral mononuclear cells by Southern blot hybridization. The re was no significant difference between the allo-BMT and the auto-PBSCT gr oups. In the allo-BMT group, the mean telomere length of recipients was 2.0 1 kb shorter than that of their donors (P = 0.008), and was 1.59 kb shorter than that of age-matched putative normal controls (P = 0.002), Telomere sh ortening in the allo-BMT group was equivalent to 41.4 years of aging in the donors, and to 52.4 years of aging in the normal controls, The mean telome re length in the auto-PBSCT group was 2.36 kb shorter than that of the age- matched putative controls (P = 0.043), which was equivalent to 61.5 years o f aging in normal controls. The extent of telomere shortening in the allo-B MT group showed a trend to negative correlation with the number of mononucl ear cells infused. These findings suggest that hematopoietic stem cells aft er HSCT lose telomere length and these shortened telomeres may result in a higher incidence of clonal disorders later in life.