30% of Japanese may face rejection after iPS-cell transplants

August 25, 2017

KYOTO- Some 30 percent of Japanese people may experience rejection after receiving transplants of cells developed from induced pluripotent stem, or iPS, cells of unrelated people, a Japanese research team has found.

The team, including Hiroshi Kawamoto, professor at Kyoto University's Institute for Frontier Life and Medical Sciences, also discovered that such reactions can be avoided by modifying some genes of the cells that are transplanted.

The research results were published on the online edition of the US journal Stem Cell Reports.

"Although 30 percent is a figure that cannot be ignored, the problem will become trivial if the genes are modified and immunosuppressants are used," Kawamoto said.

In iPS cell-based regenerative medicine, iPS cells stocked in advance are mainly used, because producing such cells from cells acquired from the patients costs time and money.

But experts note the possibility that the patients' immune systems may reject transplanted cells derived from other people.

Through experiments in test tubes, Kawamoto's team found that rejection of cells made from other people's iPS cells occurs mainly when the types of human leukocyte antigens, or HLA, which play a critical role in immune reactions, do not match between the donor and recipient sides.

Based on the experiments, the team estimates that about 30 pct of Japanese people experience such rejection. Jiji Press