In order to prepare for any future stem cell transplants required as a result of accidental exposure to high doses of radiation during clean up, Fukushima workers have been advised to store their own blood now, Japanese experts wrote in the medical journal The Lancet today. Undergoing stem cell transplantation using their own cells – termed autologous transplant – is an option that should be available to them, the authors stress.

The Lancet Correspondence was represented by Dr Tetsuya Tanimoto, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, and Dr Shuichi Taniguchi, Toranomon Hospital, Tokyo.

They wrote:

“The danger of a future accidental radiation exposure is not passed, since there has been a series of serious aftershocks even (during) this April.”

Rapidly dividing cells are vulnerable to radiation damage, which can depress bone marrow from a dose of approximately 2 Gy or more. Examples of cells that divide rapidly include reproductive germ cells, hemopoietic cells, and the cells of the intestinal tract. Hemopoietic (hematopoietic) cells are known as precursor cells – they can eventually become any of several types of blood cells.

Using stem cells from a donor for transplantation, known as allogeneic stem-cell transplantation, in previous nuclear accidents has had its problems, such as graft failure, graft-versus-host disease, profound immune suppression after transplantation, and delays in trying to find a donor.

The authors say the workers’ own peripheral blood stem cells should be used in case of future transplant needs. Using one’s own blood does away with the need for immunosuppressant medications which make the patient very vulnerable to infections, there is no graft-versus-host disease, and no time is wasted hunting around for a donor.

Autologous transplantation can restore normal hemopoietic functionality much more quickly. Collecting the blood has been proven to be safe, and the cells can be frozen and stored.

The stored blood would also be useful for treating future leukemia, a type of cancer linked to radiation exposure. Bone marrow defects could also be treated.

However, the authors add that autologous transplant has its limitations too – it can only address bone injury, and not other tissues, such as skin, lung or GI tract.

The scientists add that there are 107 transplant teams on stand-by in Japan ready to collect and store hemopoietic stem cells from workers who are bravely trying to hold back the radiation. Over 50 European hospitals are also available to help out.

The Nuclear Safety Commission of Japan is concerned about the “physical and psychological burden for nuclear workers”. The Commission adds that there is “..no consensus among international authoritative bodies, and no sufficient agreement among the Japanese public.”

The authors said:

“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. (conclusion) 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. “

“Safety of workers at the Fukushima Daiichi nuclear power plant”

Tetsuya Tanimoto, Naoyuki Uchida, Yuko Kodama, Takanori Teshima, Shuichi Taniguchi

The Lancet DOI:10.1016/S0140-6736(11)60519-9

Written by Christian Nordqvist