Aim: Luminex-based platforms have revolutionsed the detection of anti-HLA antibodies. However, single antigen beads (SAB) reactions can sometimes give rise to false positive results that can potentially interfere the assignment of specific antibodies. Recently, a new platform has been established that utilises a single antigen chip array to detect HLA antibodies, called HISTO SPOT® HLA AB. Here, we compared the performance of HISTO SPOT® HLA AB compared to Luminex-based platforms to decipher questionable antibody profiles.
Methods: Serum (n=30) from transplant waitlisted patients was selected for this study had been previously analysed using OneLambda (OLI) SAB kits. Samples included clear positive and clear negative results and those that yielded results consistent with spurious bead activity. Serum was diluted, transferred into HISTO SPOT transwells containing immobilized HLA antigens and the assay run on the MR.SPOT® processor as per manufacturer’s instructions. Results were interpreted using the HISTO MATCH HLA AB software.
Results: Samples with clear positive and negative results were broadly consistent between OLI SAB and HISTO SPOT® HLA AB. Samples believed to be spurious bead activity were more challenging to interpret between the different platforms. In some cases, the corresponding antigens were negative using HISTO SPOT® HLA AB, but often accompanied by positive results that were negative using OLI SAB.
Conclusions: The HISTO SPOT® HLA AB is a user-friendly platform that may be useful as an alternative or complementary technique to Luminex-based platforms. However, investigations of suspected false positive reactions require the utilisation of multiple technologies including different SAB kits, different platforms and the addition of crossmatching techniques to be confident in the assignment of HLA antibodies.