Feasibility of a National Class II Matching Strategy for Pediatric Kidney Transplant Candidates
1University of British Columbia, Vancouver, Canada
2Canadian Blood Services, Ottawa, Canada
3University of Toronto, Toronto, Canada.
Meeting: 2018 American Transplant Congress
Abstract number: 58
Keywords: Antibodies, Graft survival, HLA matching, MHC class II
Session Information
Session Name: Concurrent Session: Kidney: Pediatrics - 1
Session Type: Concurrent Session
Date: Sunday, June 3, 2018
Session Time: 2:30pm-4:00pm
Presentation Time: 3:18pm-3:30pm
Location: Room 3AB
Antibody-mediated rejection (AMR) is a major concern for allograft failure, which could be mitigated by allocation of Class II matched donors. Since children have priority, we used national data to model access to zero-mismatched donors for pediatric kidney recipients.
Deceased donors registered in the Canadian Transplant Registry (CTR) since 2008 with high-resolution HLA typing (n=1661) and data from the Canadian Organ Transplant Register were used for modelling of ABO:DRB1:DQA:DQB (0MM) allele combination frequencies in the population. A prospective national pediatric cohort (n=43) and the CTR were used to model wait time for an ideally matched donor (Age 12-35, 0MM), not accounting for sensitization.
460 distinct ABO:DRB1:DQA:DQB allelic combinations were identified and 214 (12.9%) were unique to a single donor. The most common (1st quintile) had a median frequency of 1.02% (IQR 0.90-1.26%) and the least common (5th quintile) 0.06% (IQR 0.06-0.06%). Using each donor type to simulate potential recipients, common ABO:HLA types (1st quintile) had 0MM to 3.9% of the donor pool and access decreased by quintile (1.9, 1.3, 0.9, 0.2% for quintiles 2, 3, 4, 5 respectively, P<0.001).
Using the mean national donor rate (412/yr), we estimated mean wait time for each ABO:HLA type quintile to be 23, 47, 68, 98 & 443 days. Feasibility was tested in an independent cohort and identified median donor 0MM frequency of unselected 14.1 (IQR 6.8, 29.2) donors/yr, of which 2.9 (IQR 1.1, 6.0) donors/yr were aged 12-35 years. Anchored by the date of actual transplant, subsequent wait time for a 12-35 year old, 0MM donor would have been a median of 97 (IQR 34-344) additional days, but with 20% waiting >365 days.
A national strategy for ABO, class II and age-matching is feasible with acceptable wait times. It is expected to advantage the majority of pediatric transplant recipients and avoid risk of AMR by avoidance of class II HLA mismatch.
CITATION INFORMATION: Blydt-Hansen T., Klement W., Tinckam K., Gill J. Feasibility of a National Class II Matching Strategy for Pediatric Kidney Transplant Candidates Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:
Blydt-Hansen T, Klement W, Tinckam K, Gill J. Feasibility of a National Class II Matching Strategy for Pediatric Kidney Transplant Candidates [abstract]. https://atcmeetingabstracts.com/abstract/feasibility-of-a-national-class-ii-matching-strategy-for-pediatric-kidney-transplant-candidates/. Accessed May 13, 2025.« Back to 2018 American Transplant Congress