HLA antibody affinity determination. From HLA‐specific monoclonal antibodies to donor HLA specific antibodies (DSA) in patient serum

Organs transplanted across donor‐specific HLA antibodies (DSA) are associated with a variety of clinical outcomes, including a high risk of acute kidney graft rejection. Unfortunately, the currently available assays to determine DSA characteristics are insufficient to clearly discriminate between potentially harmless and harmful DSA. To further explore the hazard potential of DSA, their concentration and binding strength to their natural target, using soluble HLA, may be informative. There are currently a number of biophysical technologies available that allow the assessment of antibody binding strength. However, these methods require prior knowledge of antibody concentrations. Our objective within this study was to develop a novel approach that combines the determination of DSA‐affinity as well as DSA‐concentration for patient sample evaluation within one assay. We initially tested the reproducibility of previously reported affinities of human HLA‐specific monoclonal antibodies and assessed the technology‐specific precision of the obtained results on multiple platforms, including surface plasmon resonance (SPR), bio‐layer interferometry (BLI), Luminex (single antigen beads; SAB), and flow‐induced dispersion analysis (FIDA). While the first three (solid‐phase) technologies revealed comparable high binding‐strengths, suggesting measurement of avidity, the latter (in‐solution) approach revealed slightly lower binding‐strengths, presumably indicating measurement of affinity. We believe that our newly developed in‐solution FIDA‐assay is particularly suitable to provide useful clinical information by not just measuring DSA‐affinities in patient serum samples but simultaneously delivering a particular DSA‐concentration. Here, we investigated DSA from 20 pre‐transplant patients, all of whom showed negative CDC‐crossmatch results with donor cells and SAB signals ranging between 571 and 14899 mean fluorescence intensity (MFI). DSA‐concentrations were found in the range between 11.2 and 1223 nM (median 81.1 nM), and their measured affinities fall between 0.055 and 24.7 nM (median 5.34 nM; 449‐fold difference). In 13 of 20 sera (65%), DSA accounted for more than 0.1% of total serum antibodies, and 4/20 sera (20%) revealed a proportion of DSA even higher than 1%. To conclude, this study strengthens the presumption that pre‐transplant patient DSA consists of various concentrations and different net affinities. Validation of these results in a larger patient cohort with clinical outcomes will be essential in a further step to assess the clinical relevance of DSA‐concentration and DSA‐affinity.

Schlagwörter

Fachgebiet (DDC)

500 - Naturwissenschaften und Mathematik

Projekt

Veranstaltung

Startdatum der Ausstellung

Enddatum der Ausstellung

Startdatum der Konferenz

Enddatum der Konferenz

Datum der letzten Prüfung

ISBN

ISSN

2059-2302
2059-2310

Sprache

Englisch

Während FHNW Zugehörigkeit erstellt

Ja

Zukunftsfelder FHNW

Publikationsstatus

Veröffentlicht

Begutachtung

Peer-Review der ganzen Publikation

Open Access-Status

Hybrid

Lizenz

Zitation

HUG, Melanie N., Sabrina KELLER, Talea MARTY, Daniel GYGAX, Dominik MEINEL, Peter SPIES, Joëlle HANDSCHIN, Marc KLEISER, Noemi VAZQUEZ, Janina LINNIK, Rico BUCHLI, Frans CLAAS, Sebastiaan HEIDT, Cynthia S. M. KRAMER, Suzanne BEZSTAROSTI, Jar‐How LEE, Stefan SCHAUB und Gideon HÖNGER, 2023. HLA antibody affinity determination. From HLA‐specific monoclonal antibodies to donor HLA specific antibodies (DSA) in patient serum. HLA. 16 Mai 2023. Bd. 102, Nr. 3. DOI 10.1111/tan.15047. Verfügbar unter: https://doi.org/10.26041/fhnw-5377

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