A Calculated Panel Reactive Antibody (CPRA) Calculator Supporting Both Allele-Level and Antigen-Level HLA Specificities
1Tulane University School of Medicine, New Orleans
2National Marrow Donor Program / Be The Match, Minneapolis
3Cedars-Sinai Heart Institute, Los Angeles
4Baylor Scott and White, Temple.
Meeting: 2018 American Transplant Congress
Abstract number: B106
Keywords: Allocation, HLA antibodies, HLA antigens, Kidney transplantation
Session Information
Session Name: Poster Session B: Kidney Deceased Donor Allocation
Session Type: Poster Session
Date: Sunday, June 3, 2018
Session Time: 6:00pm-7:00pm
Presentation Time: 6:00pm-7:00pm
Location: Hall 4EF
Introduction:
The number of HLA alleles represented on Luminex assays has increased over time, allowing for improved characterization of anti-HLA antibody specificity. Calculated Panel Reactive Antibody (CPRA) values, which measure the level of sensitization for transplant candidates, are based on the list of unacceptable HLA specificities determined from these antibody assays. We aimed to develop a web tool that would accurately measure CPRA when presented with any combination of unacceptable UNOS antigens and high-resolution HLA alleles.
Methods:
Because the UNOS CPRA reference panel lacked frequency data for high-resolution alleles, we utilized published haplotype frequencies derived from 6.59 million stem cell donors from the National Marrow Donor Program (NMDP) registry as a reference panel for CPRA. The NMDP frequencies have been well-validated for use in matching algorithms in stem cell transplantation. An allele-to-antigen mapping table was developed to calculate antigen frequencies from the high-resolution NMDP data.
Results:
We present a web-based CPRA calculator based on NMDP haplotype frequencies that allows for entry of a list of unacceptable HLA specificities containing any combination of high-resolution alleles and UNOS antigens. Antigen frequencies between UNOS and NMDP panels had a high degree of similarity, indicating that use of NMDP frequencies is feasible for this application. The tool is available at https://transplanttoolbox.shinyapps.io/cpra-allele/.
Conclusion:
More sophisticated handling of HLA specificities in kidney transplant informatics tools is necessary to keep pace with advancements in HLA typing and antibody assays. This work addresses the issue that selection of high-resolution HLA allele specificities in the current UNOS CPRA calculator does not increment CPRA values, and sets a foundation to move towards epitope-based matching.
CITATION INFORMATION: Gragert L., Kransdorf E., Kaur N., Maiers M., Kobashigawa J., Pando M. A Calculated Panel Reactive Antibody (CPRA) Calculator Supporting Both Allele-Level and Antigen-Level HLA Specificities Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:
Gragert L, Kransdorf E, Kaur N, Maiers M, Kobashigawa J, Pando M. A Calculated Panel Reactive Antibody (CPRA) Calculator Supporting Both Allele-Level and Antigen-Level HLA Specificities [abstract]. https://atcmeetingabstracts.com/abstract/a-calculated-panel-reactive-antibody-cpra-calculator-supporting-both-allele-level-and-antigen-level-hla-specificities/. Accessed July 12, 2025.« Back to 2018 American Transplant Congress