Emergence of Anti-HLA Antibodies after Catch-Up Vaccinations in Pediatric Kidney Transplant Candidates
1University Health System, The University of Texas at Austin, College of Pharmacy, Pharmacotherapy Division, Austin, TX, The University of Texas Health Science Center at San Antonio, San Antonio, TX, 2University Health System, The University of Texas Health Science Center at San Antonio, San Antonio, TX
Meeting: 2019 American Transplant Congress
Abstract number: 137
Keywords: Histocompatibility, Histocompatibility antigens, HLA matching, Immunogenicity
Session Information
Session Name: Concurrent Session: Kidney: Pediatrics I
Session Type: Concurrent Session
Date: Sunday, June 2, 2019
Session Time: 4:30pm-6:00pm
Presentation Time: 5:42pm-5:54pm
Location: Room 304
*Purpose: Evaluate anti-HLA antibody (Ab) emergence after catch-up vaccinations in pediatric kidney transplant candidates (PKTC).
*Methods: A single center retrospective review of PKTC < 18 years old receiving catch-up vaccinations between 2/2017 to 11/2018 was conducted. Emergence of de novo anti-HLA Ab 3 to 4 weeks post catch-up vaccinations detected by single antigen assay was evaluated. Secondary endpoints included change in anti-HLA Ab mean fluorescence intensity (MFI) > 25% from baseline, as well as change in anti-HLA Ab MFI strength, categorized as weak: 1000 – 2999 MFI; moderate: 3000 – 9999 MFI; strong: > 10,000 MFI.
*Results: 40 vaccinations were administered to 9 patients. A total of 74 potential anti-HLA Abs were detected in 3 patients, all with no history of sensitizing events from time of evaluation to follow-up. 28/74 (37.8%) antibodies detected were potential de novo anti-HLA Ab (6 Class I and 22 Class II) at 3 to 4 week post-vaccination follow-up, originating from 3 patients (33.3%). Most (78.6%) potential emergent Ab were Class II (p<0.0001). After supporting antibody testing, only 2 of the initial 28 potential de novo Ab were determined to be HLA specific; the remaining 26 were deemed non-specific. Median MFI increase in nonspecific and de novo anti-HLA Ab is reported in Table 1. 26/28 (92.9%) nonspecific Ab achieved > 25% MFI increase at 3 to 4 week follow-up. 8/9 patients included in the study continued to transplant.
*Conclusions: Vaccination resulted in a significant increase in median MFI from baseline to 3 to 4 week follow-up, although a majority of observed changes were deemed non-specific responses, possibly to denatured antigens on single antigen beads, as only two confirmed de novo anti-HLA antibodies were detected. These data suggest that there is limited clinical impact of vaccinations on emergence of de novo anti-HLA Ab, although there appears to be an association with nonspecific antibody response. Identification of nonspecific Ab responses detected by single antigen testing aids definition of true de novo anti-HLA Ab, increasing the accuracy of donor selection.
To cite this abstract in AMA style:
Sweiss H, Lyons J, Ranch D, Hitchman K, Kincaide E, Crowther B. Emergence of Anti-HLA Antibodies after Catch-Up Vaccinations in Pediatric Kidney Transplant Candidates [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/emergence-of-anti-hla-antibodies-after-catch-up-vaccinations-in-pediatric-kidney-transplant-candidates/. Accessed May 8, 2025.« Back to 2019 American Transplant Congress