“Unexpected” Positive Crossmatchs in Zero-HLA-A-B-DR Mismatched or HLA-DR-Matched Organs
1Transplant Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL
2Gift of Hope Organ and Tissue Donor Network, Itasca, IL
3Center for Transplantation, University of Kansas Medical Center, Kansas City, KS.
Meeting: 2015 American Transplant Congress
Abstract number: A85
Keywords: Flowcytometry crossmatching, HLA matching, Kidney/pancreas transplantation, Public policy
Session Information
Session Name: Poster Session A: Kidney Antibody Mediated Rejection
Session Type: Poster Session
Date: Saturday, May 2, 2015
Session Time: 5:30pm-7:30pm
Presentation Time: 5:30pm-7:30pm
Location: Exhibit Hall E
Deceased donor kidney allocation is currently prioritized by HLA-A,-B and-DR serologic matching, which disregards both specificity at the allele level, and the contributions of HLA-C,-DQ, and-DP loci. These oversights lead to “unexpected” positive crossmatch (XM) results, which are especially devastating when kidneys are shipped across the country.
To better assess the impact of the above policy, we evaluated deceased donor XM performed for our center over 28 months period. A total of 34 serologic zero-HLA-A-B-DR mismatched and 207 serologic HLA-DR matched donor-recipient pairs were identified. HLA typing was performed for HLA-A,-B,-C,-DRB1,-DRB3/4/5,-DQA1,-DQB1,-DPA1 and-DPB1 loci, providing intermediate (IR) to high-resolution (HR) typing. HLA donor specific antibodies (DSA) presence was determined by luminex antibody testing.
In the zero-HLA-A-B-DR mismatched group, 11/34 were 0% PRA; 5/34 (15%) XM were positive. One positive XM was due to HLA-DPB1 DSA and 3 had weak HLA-C or -DPB1 DSA with negative XM, adding to 4/34 (12%) donor-recipient pairs with true HLA DSA. In the HLA-DR-matched group, 58/207 were 0% PRA; 64/207 (31%) XM were positive. HLA-class I DSA was not considered for this analysis, as the patients were not deemed HLA-A-B matched. HLA-DSA to DQB1, DPB1 or DRB1 alleles was detected in 24/64 (37%) of the positive XM. Six additional pairs had weak DSA with negative XM, adding to 30/64 (47%) pairs with true HLA class II DSA.
HLA matching between donor and recipient for solid organ transplantation is desirable as it will assure a negative XM pre-transplant, and more importantly will minimize the potential generation of de novo DSA post-transplant. Albeit this approach is not practical, efforts should be made to maximize compatibility between donor and recipient. The data presented here clearly demonstrate that “matching” for HLA-DR (serologically) does not assure absence of HLA-class II DSA. Moreover, DSA for either class I or class II antigens were found even in zero-HLA-A-B-DR mismatch donor-recipient pairs. Kidney allocation policies in sensitized patients should include IR/HR typing of all donor HLA loci and the complete antibody profile of the transplant candidate.
To cite this abstract in AMA style:
Haarberg K, Cusick M, Abecassis M, Jaramillo A, Kaplan B, Tambur A. “Unexpected” Positive Crossmatchs in Zero-HLA-A-B-DR Mismatched or HLA-DR-Matched Organs [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/unexpected-positive-crossmatchs-in-zero-hla-a-b-dr-mismatched-or-hla-dr-matched-organs/. Accessed May 18, 2025.« Back to 2015 American Transplant Congress