In Correspondence published Online First and an upcoming Lancet, Japanese experts suggest that blood products be taken from workers dealing with the ailing Fukushima Nuclear Facility-so that, should they accidently be exposed to high and health-damaging doses of radiation during the clean-up operation, they will be able to receive treatment by undergoing stem cell transplanation using their own cells (autologous transplant). The Correspondence authors are represented by Dr Shuichi Taniguchi, Toranomon Hospital, Tokyo, Japan, and Dr Tetsuya Tanimoto, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
The authors say: "The danger of a future accidental radiation exposure is not passed, since there has been a series of serious aftershocks even [during] this April."
Generally, rapidly dividing cells, such as intestinal-tract cells, reproductive germ cells essential for fertility, and haemopoietic cells, are most vulnerable to radiation, which can depress bone marrow from a dose of about 2 Gy or higher. Haemopoietic cells are the precursor stem cells that later become a wide range of different blood cells in the body.
In previous nuclear disasters and accidents, allogeneic stem-cell transplantation (ie stem cells from a donor) has been used, But this has major limitations, such as time-consuming donor searching, graft failure, graft-versus-host disease (GVHD), or profound immune suppression after transplantation.
Instead of this, the Japanese call for collection of the peripheral blood stem cells (PBSC) of the workers themselves so that they could have future transplants should the need arise. This technique has several advantages over allogeneic transplantation; it does not cause GVHD, and does not require immunosuppressant drugs that make radiation victims even more vulnerable to infection. Further, the technique can more rapidly restore normal haemopoietic functionality in the body, the safety of the collection method is proven, and the cells are easy to freeze and store. Finally, it could be used to treat future leukaemia (a known possibility of radiation exposure) as well as bone marrow defects. But the authors also acknowledge autologous transplant is not perfect since it can rescue injury of bone marrow only and not other tissues, such as gastrointestinal tract, skin, or lung.
The authors say that 107 transplant teams are standing by in Japan to collect and store haemopoietic stem cells from the workers who are striving to restrain the radiation, and more than 50 hospitals in Europe have agreed to help the workers if required. But the Nuclear Safety Commission of Japan is resisting the plan, due to the "physical and psychological burden for nuclear workers", and there being "no consensus among international authoritative bodies, and no sufficient agreement among the Japanese public."
Tanimoto, Taniguchi and colleagues add: "The most important mission is to save the nuclear workers' lives and to protect the local communities. Such an approach would be the industry's best defence: if a fatal accident happened to the nuclear workers, the nuclear power industry of Japan would collapse."
They conclude: "The process to completely shut down the reactors in Fukushima is expected to take years. The risk of accidental radiation exposure will thus accumulate for the nuclear workers and banking of their autologous PBSCs will become increasingly important. A judgment of right or wrong on this scheme must be determined from the standpoint of the nuclear workers and their families, not from a point of view of cost-benefit balance in ordinary times. Toranomon Hospital in Tokyo is ready to harvest and bank autologous PBSCs for the nuclear workers upon request."
Source
The Lancet
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