Korean J Transplant.  2023 Nov;37(Suppl 1):S263. 10.4285/ATW2023.F-8619.

Pretransplant immunologic risk assessment in high baseline ABO antibody titers and donor-specific anti-human leukocyte antigen antibodies in ABO incompatible kidney transplantation

• Mehrotra S
• Sharma RK
• Kapoor R
• Tiwari A
• Kumar A
• Agarwal MM
• Srivastava A
• Bhaskar V
• Kumar R

• KMID: 2551892
• DOI: http://doi.org/10.4285/ATW2023.F-8619

Abstract

Background
Twenty patients were evaluated for donor specific anti-human leukocyte antigen (HLA) sensitization before they received ABO incompatible kidney transplantation in our center from 2021 to 2022. Each recipient was evaluated by complement dependent cytotoxicity crossmatch, flow crossmatch and single antigen bead assay (SAB). Titers of anti-A and/or Anti-B are monitored on daily basis with target levels being <1:8 on the day of transplant.
Methods
Blood grouping and irregular antibody screening test of all patient and donor samples was performed on fully automated immunohematology analyzer (Ortho Vision Swift Analyzer). For ABO antibody titers the gel IAT method was used. Serially diluted sample used in Ortho Gel Card having anti-human globulin C3d combined in it. After incubation at 37 °C for 15 minutes, the gel cards were centrifuged and titers were determined as the highest dilution showing 1+ agglutination. SAB was performed on Luminex platform with Immucor Lifecodes single antigen assays.
Results
High baseline ABO antibody titers (>1,000) and anti-A, anti-B both (>1,000) titers in AB positive donors with O positive recipient were not associated with antibody-mediated rejection or graft loss in our study, 3 patients (15%) expired due to COVID-19 pandemic infection, the remaining 17 patients (85%) survival and graft survival is good. Cell base cross match were negative in all recipients. Donor-specific HLA antibodies (DSA) positivity in two recipients one with class I with <1,000 MFI, present serum creatinine is 1.1 mg/dL and in second had ABMR with class II SAB positivity and >5,000 MFI present serum creatinine is 1.98 mg/dL.
Conclusions
SAB positivity with DSA mean fluorescent intensity >5,000 and high baseline titers of ABO antibody is a high risk for ABMR. Desensitization using rituximab, tacrolimus and MMF along with plasmapheresis results in successful outcome even in the presence of anti HLA and ABO sensitization.