Flowcytometry Crossmatching

About this test

The human leukocyte antigen (HLA) proteins are crucial for the body’s immune defense against potentially harmful foreign substances. Class I and II HLA (HLA I and II) proteins are the ones involved with the immune response and transplantations.

Flow cytometry cross-matching (FCXM) involves mixing donor lymphocytes, the recipient’s immune serum, and fluorescent labeled antibodies into a sample. The antibodies used are specific to the donor HLA and various T-cell and B-cell specific markers (e.g. CD3, 5, and 8 for T-cells, and CD19, 20, and 21 for B-cells).

A problem with allograft transplants is that organ rejection can occur, which is seen as a result of the recipient’s antibodies against the donor HLA. This will elicit an immune response which can subsequently cause rejection.

Since a positive FCXM is associated with an increased chance for a transplant recipient to reject the prospective transplant, FCXM is important, as it allows for donor antigens and host antibodies to be checked prior to a transplant to avoid a host immune response. This reduces the chances of acute or chronic allograft rejection.

The HLA T & B Cell Flow Cytometry Crossmatch Test is necessary for individuals who are undergoing organ transplantation. The test helps to identify the compatibility of the donor's tissue, blood, and organs with the recipient's body.

The purpose of the crossmatch is to detect the presence of antibodies in the recipient against the red blood cells of the donor. These antibodies attach to the red blood cells of the donor after transfusion. An incompatible transfusion can result in a severe hemolytic anemia and even death.

Other Names – Flow Crossmatch, FCXM, HLA Crossmatch, HLA Crossmatch by flowcytometry, Organ Transplantation test, Kidney transplant test, stem cell transplantation, liver transplant test

Flow cytometry can be used to analyze different cell types. This technique can be applied to immunology to ensure that, prior to a transplant procedure, interactions between donor and recipient immune components do not cause an adverse immune reaction.

Class I and II HLA (HLA I and II) proteins are the ones involved with the immune response and transplantations. HLA I proteins are expressed on the surface of all cells. Conversely, HLA II proteins are expressed on the surface of antigen presenting cells (APCs) of the immune system, such as Dendritic cells and B-Cells.

HLA proteins are highly varied, as three genes contribute to the formation of HLA I proteins, while six genes contribute to the formation of HLA II proteins. Given that there are two distinct alleles for each gene, the possible combinations are numerous.

Flow crossmatch helps to identify the compatibility of the donor's tissue, blood, and organs with the recipient's body. The purpose of the crossmatch is to detect the presence of antibodies in the recipient against the red blood cells of the donor.