Transplantation of allogeneic iPSCs without immunosuppression

Japanese have learned how to transplant donor stem cells

Denis Strigun, Naked Science

Japanese biologists have developed a technique for transplantation of induced pluripotent stem cells (iPSC) from a donor that does not require the use of immunosuppressants. The results of the work are presented in Stem Cells Reports (Sugita et al., Successful Transplantation of Retinal Pigment Epithelial Cells from MHC Homozygote iPSCs in MHC-Matched Models).

Induced stem cells (iSC) are the result of reprogramming somatic, reproductive or pluripotent cells into stem cells. The latter can develop into cells of other organs and tissues. As a self-renewing biomaterial, they are transplanted, for example, to patients with lymphoma or leukemia. The difficulty of using such therapy lies in the fact that ISCs must be reprogrammed from the cells of the patient himself and at a natural rate. The procedure is expensive and lengthy: the waiting period for the operation exceeds one year.

The need to use the patient's own cells is explained by the rejection of ISCs reprogrammed from donor cells. In such cases, immunosuppressive therapy is used to suppress the immune response to the transplanted biomaterial. In a new study, scientists tested an alternative way of selecting donor iPSCs (pluripotent) – according to the main histocompatibility complex (MHC). The MHC is a vast region of the genome that is involved in coordinating the actions of various cells of the immune system. In the case of humans, MHC corresponds to human leukocyte antigen (HLA).

In the experiment, the scientists used iPSC from a database of stem cells reprogrammed from the cells of some monkeys and transplanted to others. Subsequently, the transplanted iPSCs had to not only take root, but also differentiate into retinal pigment epithelium cells. The results showed that if the MHC of the donor and the patient matched, the stem cells were not rejected for six months. Thus, immune T cells did not respond to the transplanted biomaterial. In turn, when the MHC mismatch occurred, rapid rejection occurred.

At the second stage of the work, the authors repeated the experiment on ex vivo human cell culture. The results were comparable. According to Dr. Sunao Sugita, further studies will clarify and probably consolidate the data obtained.

"In order for iPSC transplantation to enter medical practice, we need to create banks of iPSC reprogrammed from anyone's cells that can be transplanted to anyone. Nevertheless, the immune response and rejection are still a big problem for this area," the scientist said.

Portal "Eternal youth" http://vechnayamolodost.ru  16.09.2016