Bead-by-bead normalization of single antigen assays: A necessary step for accurate detection of weak anti-HLA antibodies.

Ascertaining the presence of weakly positive anti-HLA donor-specific antibodies (DSA) in organ transplantation with multiplex single antigen beads assays may be challenging despite their high sensitivity due to technical variability issues. Through extensive datasets of Next-Generation Sequencing HLA typings and single antigen analyses, we reassessed the mean fluorescence intensity (MFI) positivity threshold of the assay to enhance accuracy. By showing that some beads were more prone to false positivity than others, we propose a nuanced approach that accounts for nonspecific intrinsic reactivities at the HLA antigen level, that is, on a bead-by-bead basis, as it enhances assay precision and reliability.

Improving HLA typing imputation accuracy and eplet identification with local next-generation sequencing training data.

Assessing donor/recipient HLA compatibility at the eplet level requires second field DNA typings but these are not always available. These can be estimated from lower-resolution data either manually or with computational tools currently relying, at best, on data containing typing ambiguities. We gathered NGS typing data from 61,393 individuals in 17 French laboratories, for loci A, B, and C (100% of typings), DRB1 and DQB1 (95.

Predictive value of mixed antigen screen beads in pre-transplant assessment of HLA immunization in solid organ transplant recipients.

Pre-transplant serum screening of anti-HLA antibodies is recommended for solid organ transplantations. Many laboratories use the less expensive bead-based screening assay as the main technique and, if positive, turn to single-antigen beads (SAB). We studied the correlations between these two immunoassays.