Results of HLA antibody testing using ELISA vs the fluorescent bead method and retrospective review of data for recipients of packed RBCs and platelets from male HLA-immunized donors

Out with the old, in with the new: Virtual versus physical crossmatching in the modern era

The virtual crossmatch (VXM) is gaining acceptance as an alternative approach to assess donor:recipient compatibility prior to transplantation. In contrast to a physical crossmatch, the virtual crossmatch does not require viable donor cells but rather relies on complete HLA typing of the donor and current antibody assessment of the recipient. Thus, the VXM can be performed in minutes which allows for faster transplant decisions thereby increasing the likelihood that organs can be shipped across significant distances yet safely transplanted. Here, we present a brief review of the past 50 years of histocompatibility testing; from the original complement-dependent cytotoxicity crossmatch in 1969 to the new era of molecular HLA typing, solid-phase antibody testing and virtual crossmatching. These advancements have shaped a paradigm shift in our approach to transplantation. That is, foregoing a prospective physical crossmatch in favor of a VXM. In this review, we undertake an in-depth analysis of the pros- and cons- of physical and virtual crossmatching.Finally, we provide objective data on the selected use of the VXM which demonstrate the value of a VXM in lieu of the traditional physical crossmatch for safe and efficient organ transplantation.

Anti-human leukocyte antigen antibodies are present in blood of blood donors: is therapy with blood preparations safe for graft recipients?

BACKGROUND

Blood products infusions are often administrated to graft recipients. Post-transfusion reactions of anti-human leukocyte antigen antibodies (anti-HLA) are responsible for transfusion-related acute lung injury, but cases of graft rejection after blood product infusions were recently also proven.

METHODS

The aim of this study was to assess, with the use of the very sensitive Luminex technology and traditional lymphocytotoxic test, the prevalence and cytotoxic activity of anti-HLA in blood donors with different medical histories to evaluate a potential risk of post-transfusion immune complications. Data were analyzed according to different normalized background cutoffs (1.5, 2.2; and the high cutoffs-10.8 for I class and 6.9 for II class anti-HLA).

RESULTS

We observed that anti-HLA may be present in 36% of donors, and even in up to 73.6% of risk groups. Significant risk factors included female sex (23.9% to 64.2% for different cutoffs) and pregnancy history (30% to 72.5%), regardless of the cutoff used in analysis, whereas sera from female donors showed lower cytotoxicity (panel reactive antibodies). Anti-HLA were also detected in men (3.7% to 37%), in donors after a transfusion (0% to 62.5%), and even with no known risk factors (3.8% to 26.9%).

CONCLUSIONS

Luminex technology is a sensitive tool in anti-HLA detection, but consensus in measurement interpretation for blood donors is needed. Selection of blood products on the basis of medical history can be a useful alternative for routine testing of blood donors. The clinical significance of treatment of graft recipients with blood products requires further study; until then, more attention should be paid to possible complications.