Olerup XM-ONE testing provides additional information to a traditional lymphocyte crossmatch. The test identifies patients at increased risk of rejection due to donor specific AECA.



Before organ transplantation is carried out, it has to be established whether or not the organ donor’s tissue will be accepted by the recipient’s immune system. 

IMMUNE-ANTIBODY-bw-150.jpgTo elucidate the degree of matching, the blood groups of the recipient and donor are first compared. They should be identical. This pre-transplant investigation also includes tissue typing of the recipient and donor to identify and compare the major transplantation antigens, known as HLA class I and II antigens. 
Traditionally, a lymphocyte crossmatch test is used to establish whether or not the recipient has antibodies to the HLA class I and II antigens expressed on the donor’s T- and B- lymphocytes. If no antibodies can be detected and the blood groups match, the transplantation can go ahead. 
Despite these precautions, and treatment with immunosuppressive drugs, a large proportion of transplanted patients experience at least one rejection episode, usually during the first three months after transplantation. In most cases, acute rejection episodes can be managed via increased doses of the immunosuppressive drugs, even though they may cause more side effects and increase the risk of infection and malignancy. Nevertheless, rejection episodes that result in early graft loss still occur in 1 to 2% of all kidney-transplanted patients. 

One important and serious factor responsible for the development of hyper-acute and early-acute rejections in a patient whose lymphocyte crossmatch test is negative (i.e. no antibodies to HLA class I and II detected) is thought to be preformed recipient non-HLA antibodies that target the endothelium (the cells that coat the inside of blood vessels) in the transplanted donor organ. This is particularly important because the endothelium is the first tissue that the patient’s blood encounters. Until recently, it has been impossible to test for the presence of such donor-specific anti-endothelial cell antibodies. 

Olerup XM-ONE is a endothelial crossmatch test that enables rapid detection of any specific anti-endothelial cell antibodies as well as antibodies to HLA class I and II antigens that are also expressed on endothelial cells. 

The Olerup XM-ONE crossmatch test kit detects the presence of recipient IgM and IgG antibodies to donor endothelium using flow cytometry — a method that is today used in many tissue-typing laboratories for lymphocyte crossmatch testing and which takes only 3 hours.