Allogeneic marrow grafts from donors with congenital chromosomal abnormalities in marrow cells

Donor-derived 47, XXY in an unrelated cord blood transplant recipient

A 65-year-old Japanese male with therapy-related myelodysplastic syndrome was admitted for unrelated cord blood transplantation. A cord blood unit from a male donor was obtained from the Japan Cord Blood Bank Network. The patient then received a conditioning regimen consisting of fludarabine, intravenous busulfan, and total body irradiation. Successful engraftment was obtained. The bone marrow examination on day 28 revealed trilineage engraftment, and chimerism analysis by variable number of tandem repeat polymerase chain reaction confirmed complete donor chimerism. At that time, conventional cytogenetics of the bone marrow aspirate showed 20 out of 20 metaphases with the 47, XXY karyotype characteristic of Klinefelter syndrome. Klinefelter syndrome is the most common genetic cause of human male infertility with a reported prevalence of 0.1–0.2% in the general population. In Japan Cord Blood Bank Network, there is no informed consent from parents about the possibility that post-unrelated cord blood transplantation patient evaluation may reveal donor-origin inherited diseases including cytogenetic abnormality. It is desirable to have opportunities in Japan discussing whether parents will be notified of the possibility that post-unrelated cord blood transplantation evaluation may reveal donor-derived illness incidentally.

Influence of telomere length on short-term recovery after allogeneic stem cell transplantation

OBJECTIVE

Telomeres shorten in somatic cells during aging and states of increased turnover, including hematopoietic stem cell transplantation. Fast hematopoietic recovery is critical for the patients' course after hematopoietic stem cell transplantation. It is unknown whether telomere length in hematopoietic stem cells (HSCs) predicts short-term hematopoietic recovery.

METHODS

We quantified telomere length by flow fluorescence in situ hybridization analysis in HSCs and granulocytes of healthy stem cell donors and monitored time to peripheral blood cell recovery in transplanted hosts. Furthermore, we measured in vitro repopulation potency of HSCs by assaying for colony-forming units granulocyte-macrophage (CFU-GM).

RESULTS

Telomere length in HSC shortens continuously in vivo and is comparable to telomere length in granulocytes from the same individual. Numbers of in vitro formed CFU-GM per HSC show an inverse relationship to age and telomere length. However, telomere length in HSCs was not correlated with short-term recovery after HSC transplantation.

CONCLUSION

These findings suggest that healthy stem cell donors have sufficient telomere length reserve to repopulate a myeloablatively treated host, despite continuous aging of HSCs in vivo and decreased repopulation ability of HSCs from older donors in vitro.

Efficacy and toxicity of radiation in preparative regimens for pediatric stem cell transplantation. I: Clinical applications and therapeutic effects

Here, we review the role of total body irradiation in the treatment of children with bone marrow transplantation, as well as alternative sources of stem cells. We were unable to demonstrate any clear superiority of TBI-containing preparative regimens, but we were able to find a few definitive reports of significantly enhanced toxicity or important variations in control of the underlying primary diseases, in comparing TBI-based regimens, with those containing only chemotherapy.