Does the human leukocyte antigen's relatively homogeneous genetic background relate to better lung transplantation outcomes in Japan?

The outcomes of lung transplantation in Japan are better than in other countries; however, the reasons for this are unclear. While the genetic background of the Japanese may be relatively homogeneous compared with those of other countries, whether this genetic similarity is related to better lung transplantation outcomes is an interesting question. We reviewed the literature to define the relationship between genetic similarity and better lung transplantation outcomes. However, it is still difficult to directly describe the relationship between genetic background and lung transplantation outcomes. As another approach, racial match or mismatch lung transplantation helps investigate whether genetic background similarity contributes to better outcomes of lung transplantation. Some reports have evaluated the impact of donor/recipient race-matching, which does not sufficiently influence patient outcomes to factor into organ transplant offers. Matching is not beneficial for African American lung transplant recipients. This may indicate that other factors influence the outcomes of these transplants. However, to discuss racial mismatch transplantation, racial disparities in organ transplantation need to be understood because the outcomes of organ transplantation differ between recipients of different races regardless of mismatched or matched organ transplantation. This makes it difficult to understand the outcome of a racially matched or mismatched lung transplantation. Meanwhile, in cadaveric liver and kidney transplantations, there is no difference in the outcomes in Japan and in other countries. In conclusion, it remains difficult to determine whether similarity in genetic backgrounds is related to better lung transplantation outcomes in Japan.