BSHI and BTS UK guideline on the detection of alloantibodies in solid organ (and islet) transplantation

Abstract

Solid organ transplantation represents the best (and in many cases only) treatment option for patients with end‐stage organ failure. The effectiveness and functioning life of these transplants has improved each decade due to surgical and clinical advances, and accurate histocompatibility assessment. Patient exposure to alloantigen from another individual is a common occurrence and takes place through pregnancies, blood transfusions or previous transplantation. Such exposure to alloantigen's can lead to the formation of circulating alloreactive antibodies which can be deleterious to solid organ transplant outcome. The purpose of these guidelines is to update to the previous BSHI/BTS guidelines 2016 on the relevance, assessment, and management of alloantibodies within solid organ transplantation.

Exploring the immunological relevance of pre‐transplant donor‐specific antibody in intestinal transplantation, with special consideration to the liver

“…Here, our results somewhat indicate that DSA affects post-ITx outcomes poorly and that HLA class I in the context of LITx seems to be less detrimental to outcomes. This is in line with previous (NHSBT BAG, 2013) and recently updated guidelines for immunological risk in ITx(Battle et al, 2023). As our clinical transplant team at CUH has become more familiar with Luminex SAB reporting, alongside discussion regarding immunological risk, the H&I laboratory also now tends to discuss pre-transplant DSA MFI levels (despite the semi-quantitative nature of the assay) at the time an offer is received.…”

“…Serum for SAB testing was pre-treated with ethylenediaminetetraacetic acid to negate assay inhibitory effects due to complement (Battle et al, 2023;Schnaidt et al, 2011) Where there were multiple beads for one DSA specificity, the bead…”

“…Avoidance of pre-transplant DSA at the time of transplantation is a main theme throughout most SOT programmes in preventing allograft rejection, graft loss and early mortality (BSHI & BTS, 2014;Battle et al, 2023;Terasaki, 2003). The relevance of pre-transplant DSA in ITx has been more difficult to establish as the number of ITx cases worldwide per year is so few; there are still significant gaps in our understanding, and worldwide consensus guidelines are lacking.…”

Predicting flow cytometry crossmatch results from single‐antigen bead testing

“…These samples were negative for DSA using SAB, even though all donor-directed HLA antigens were represented in the SAB panels. Positive FCXM results are not considered to be clinically significant in the absences of detectable DSA according to the BSHI, BTS antibody guidelines (Battle et al, 2023;Howell et al, 2010). Guidelines published by the Cardiothoracic Advisory Group of the British Transplantation Society recommend that when DSAs are directed against antigens for which the donor is homozygous, the MFI of the DSA should be doubled, assuming a corresponding increase in the level of expression of that single antigen on a transplanted graft compared with a heterozygous donor, which would express lower levels of two different antigens (Battle et al, Smith, 2013).…”

“…(DSA) using Luminex-based single-antigen bead (SAB) assays can identify antibodies present at low levels, which may not be considered a contraindication to transplantation unless it also causes a positive crossmatch (Battle et al, 2023;Howell et al, 2010). The ability to accurately predict the likelihood of DSA causing a positive crossmatch is useful to enable virtual crossmatching or to monitor responses to drug therapies such as imlifidase.…”