Longer telomere length in white blood cells from unrelated donors has been linked to increased longevity of life for those who suffer from aplastic anemia. Telomeres are the genetic sequences on the extreme ends of chromosomes which help protect the DNA inside the chromosomes. Every time a cell divides, it uses up the genetic information stored in the telomeres. When the telomeres grow too short, the cell is no longer able to replicate itself and stagnates. The length of telomeres has been linked to biological aging and the onset of age-related diseases. Aplastic anemia is a blood disorder where the bone marrow fails to make new blood cells, with one of the causes potentially being defects in telomere biology.

Shahinaz M. Gadalla, M.D., Ph.D., of the National Cancer Institute and her colleagues followed a group of 330 patients with severe aplastic anemia who received a hematopoietic (blood marrow) cell transplantation (HCT) from 1989 to 2013. They looked at the relationship between leukocytes (white blood cell) telomere lengths before the transplant with the results afterwards. The study found that the patients who received white blood cells with longer average telomere length survived on average 5 years longer. The patients who received HCT from donors with longer telomeres were 40% less likely for post-HCT mortality.

Could white blood cell telomere length become one of the factors used in choosing best available donor for any unrelated donor hematopoietic (blood marrow) cell transplantation (HCT) surgery?