Endothelial Cell Crossmatch Service

Endothelial cell (EC) is the first point of contact between the allograft and the recipient's immune system. In this process, a source of non-HLA antigens stimulates a humoral immune response. Using primary human aortic EC (HAEC) and the XM one assay, EC crossmatch (ECXM) could be used to identify patient sera containing antibodies against EC. Creative Biolabs provides ECXM assay to detect non-human leukocyte antigen (HLA) antibodies, which have been implicated in antibody-mediated rejections.

Process of ECXM

Firstly, blood is collected from the donor and peripheral blood mononuclear cells (PBMCs) are isolated. Endothelial precursor cells are then isolated and probed by recipient antibodies. The recipient antibodies are then tagged with fluorescently labeled antihuman IgG or IgM antibodies. Finally, the antibody-bound precursor cells run through a flow cytometer to determine the reactivity toward donor endothelial antigens.

Fig.1 Diagram of ECXM assay. (Gates, 2017)

Our Service

EC constitutes the first point of contact between the transplanted organ and the recipient's immune system. Antibodies reactive with donor endothelial cell antigens have been implicated in cases of humoral rejection in the absence of HLA antibodies. ECXM identifies antibodies to non-HLA antigens expressed on endothelial cells. The results are reported as the median channel shift (MCS) over the negative control sera. A positive result is >50 MCS.

Creative Biolabs provides a comprehensive ECXM service and in vitro diagnostic kit which is used for the isolation of endothelial precursor cells and preparation of samples for analysis of IgM and IgG antibodies specific for these cells.

Highlights

• EC crossmatch is performed using flow cytometry.
• Two to four EC lines are selected to avoid any HLA antibody-mediated positivity.
• EC crossmatch report shows test results as negative or positive.
• Positive EC crossmatch may indicate the presence of antibodies directed to non-HLA targets expressed on endothelial cells.
• The report also displays the strength of the crossmatch in MCS, and a comment indicating the risk of accelerated rejection.

As a leader in HLA antibody detection, Creative Biolabs offers a full range of HLA Antibody and Non-HLA Antibody detection assay for the transplant diagnostics segment. We also offer a wide range of singleplex kits. For more information, please feel free to contact us directly.

Reference

1. Gates, Katherine V., Naveen L. Pereira, and Leigh G. Griffiths. "Cardiac non-human leukocyte antigen identification: techniques and troubles." Frontiers in immunology 8 (2017): 1332. Distributed under Open Access license CC BY 4.0, without modification.