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 October 27, 2020.
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