If you know something about transplant surgery, you must know that“Matching” is an important part of transplant surgery. The success of matching is directly related to whether the recipient is suitable for receiving the corresponding kidney, and the degree of matching is also directly related to the incidence of rejection after transplantation.
So how does it work? HLA Human leukocyte antigen is involved in the body’s recognition of foreign components, so the similarity between donor and recipient HLA is a direct indicator of the probability of subsequent rejection. On this basis, the matching of kidney transplantation needs to determine whether the donor and recipient are HLA-matched, the specific means is to detect the donor and recipient HLA-a, HLA-b, HLA-dr and so on, and compare the donor and recipient HLA molecular types one to one, the greater the number of matched pairs, the smaller the probability of rejection. Although these types of matches greatly reduce the risk of rejection, a small number of HLA-matched patients still develop rejection, so the researchers turned to other Histocompatibility antigens, these include MICA, the human MHC class i-related Gene A, and the polymorphic unconventional MHC class I molecules it codes for.
Mica isn’t a new concept. Researchers have known for 30 years that these molecules are homologous to MHC class I chains, but haven’t been able to pinpoint their role in post-transplant rejection. Mica is the neighbor of HLA-B and is closely related to HLA-B types. However, there are cases in which MICA is single-changed, and conventional matching experiments can not determine the matching degree and typing of Mica. Is it necessary to test MICA alone?
In a paper published in nature medicine in May 2022, Carapito and his team proposed that testing for MICA phenotypic matching could reduce potential graft loss. The study included 1356 kidney transplant patients from six centers in France, with a median of 6.3 years of observation and a maximum of 12.9 years. The results showed that the 5-year survival rate of MICA mismatched patients was 88% , which was significantly lower than that of MICA matched patients. Among them, patients with MICA mismatched sites > 2 had a higher probability of graft loss within 5 years after surgery. Studies have also found that de novo anti-donor MICA-specific antibodies (de novo anti-MICA DSA) are a common risk factor for t cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR)[1] .
The above findings reveal the importance of preoperative MICA matching detection, some foreign transplant centers have begun to plan to gradually incorporate MICA genotyping and DSA testing into the preoperative examination of transplant candidates and postoperative care of transplant recipients [2] . The center has taken MICA antibody detection as one of the tools for postoperative evaluation of transplant recipients, and will continue to pay attention to the application of new technologies and new strategies at home and abroad, and update the clinical system in time.
References
[1]Carapito,R.,et al.,The MHC class I MICA gene is a histocompatibility antigen in kidney transplantation.Nature Medicine,2022.28(5):p.989-998.
[2]Allison,S.J.,MICA in kidney transplants.Nature Reviews.Nephrology,2022.18(5):p.273.
This article is an original article of”Kidney Transplantation, sun yat-sen hospital, Fudan University”. It is reproduced with the author’s permission and marked with the source. Care about the kidney, from the concern”Fudan University affiliated Zhongshan Hospital Kidney Transplant” public wechat start, you can also click [ read the original ] , view活体亲属供肾移植系列科普回顾
