Crossmatch assays in transplantation: Physical or virtual?: A review

Abstract

The value of the crossmatch test in assessing pretransplant immunological risk is vital for clinical decisions, ranging from the indication of the transplant to the guidance of induction protocols and treatment with immunosuppressants. The crossmatch tests in transplantation can be physical or virtual, each with its advantages and limitations. Currently, the virtual crossmatch stands out for its sensitivity and specificity compared to the physical tests. Additionally, the virtual crossmatch can be performed in less time, allowing for a reduction in cold ischemia time. It shows a good correlation with the results of physical tests and does not negatively impact graft survival. Proper communication between clinicians and the transplant immunology laboratory will lead to a deeper understanding of each patient’s immunological profile, better donor–recipient selection, and improved graft survival.

Histocompatibility Testing: A Fundamental Aspect of Renal Transplant Workup

“…Although numerous technical adjustments have been implemented to refine the sensitivity and specificity of the CDCXM test, the incorporation of anti-human globulin (AHG) is one among them. However, the inclusion of AHG does not improve this sensitivity; at times, it may even result in nonspecific binding to fragment crystallizable receptors (FcR) on B cells [11,20]. Complement activation necessitates elevated antibody concentrations, potentially impacting the test accuracy.…”

“…Several factors contribute to falsenegative outcomes, such as a low HLA expression on donor cells, an excessive number of cells, a low serum volume, low DSA levels, lymphocyte impurity, and high background in the negative control serum. False-positive results may occur due to IgG binding to FcR in B cells, a low negative control background, inadequate washing after antibody incubations, the presence of autoantibodies, and the use of therapeutic antibodies like antithymocyte globulin, rituximab (anti-CD20), alemtuzumab (anti-CD52), basiliximab (anti-CD25), and daclizumab (anti-CD25) [20]. Pronase treatment has been employed to diminish the attachment of immunoglobulins to Fc receptors and to decrease the responsiveness to therapeutic antibodies targeting CD20 in lymphocytes [21].…”

“…Overall, flow cytometry crossmatch shows a higher sensitivity than CDC crossmatch, whereas CDC crossmatch is found to be more specific than flow cytometry crossmatch [22,23]. antibodies like anti-thymocyte globulin, rituximab (anti-CD20), alemtuzumab (anti-CD52), basiliximab (anti-CD25), and daclizumab (anti-CD25) [20]. Pronase treatment has been employed to diminish the attachment of immunoglobulins to Fc receptors and to decrease the responsiveness to therapeutic antibodies targeting CD20 in lymphocytes [21].…”

“…Finding a suitable organ donor with a low risk of rejection becomes challenging when the patient has a high PRA. In such cases, clinicians may consider exploring strategies to mitigate the risk of AMR [20][21][22][23]. The effectiveness of PRA is influenced by both the composition of the panel and the methodology employed for antibody detection.…”

“…Table 4. Representation of the key differences between cell-based cross match and virtual crossmatch tests [16][17][18][19][20][21][29][30][31].…”