Session Name: Biomarkers: Clinical Outcomes II
Session Type: Rapid Fire Oral Abstract
Date: Tuesday, June 7, 2022
Session Time: 5:30pm-7:00pm
Presentation Time: 5:50pm-6:00pm
Location: Hynes Ballroom A
*Purpose: Recipients with sensitization to HLA defined by a high percentage of Panel Reactive Antibodies (PRA) or Donor-specific anti-HLA antibodies (DSA) are at higher immunologic risk for poor graft outcomes. Little is known about the prevalence and impact of circulating HLA-specific B cells (HSB) frequencies and their phenotype on graft outcomes. Utilizing a novel multiplex bead-based assay to identify and phenotype HSB, we studied the circulating HSB in kidney transplant recipients and correlated with rejection.
*Methods: PBMC taken at serial time-points from kidney transplant recipients (n=24; 14 with no rejection, 10 with rejection) were incubated with single antigen HLA-coated multiplexed beads (One Lambda) for HLA Class I and II. Using multi-parameter flow cytometry, HLA-specific B cells (HSB) were identified by the formation of HLA Bead-B-cell Rosettes (BBR) (Blue dots, Fig. A; Orange regions represent individual bead specificities). IgD/CD27 double negative HSB cells (DNB) were enumerated by plotting BBR population on IgD vs CD27 plot (Blue dots in lower left corner of dot-plot, Fig. B; Orange dots represent B cells).
*Results: DNB frequencies at 0 and 3 months post-transplant were higher (at 0 months: 0.3112 ± 0.04904 % vs 0.09946 ± 0.04111%, p=0.0032, Fig. C; at 3 months: 0.2703 ± 0.09659% vs 0.05444 ± 0.03046%, p=0.0234, Fig. D) in recipients who went on to have rejection within 1 yr post-transplant compared to those that didn’t.
*Conclusions: Pre-transplant and 3-months post-transplant HLA class II-specific IgD/CD27 Double Negative B cell frequencies assessed by a novel multiplex bead-based assay predicts rejection in kidney transplant recipients within 1 yr. These data suggest that circulating B cells specific for donor HLA antigens and their phenotype as assessed by this novel assay serve as potential biomarkers for risk stratification of kidney transplant recipients.
To cite this abstract in AMA style:Ilyas Z, Akl A, Pinelli D, Gallon L, Tambur A, Ansari M. HLA-Specific IgD/CD27 Double Negative B Cell Frequency Assessed by a Novel Multiplex Bead-Based Assay Predicts Rejection in Kidney Transplant Recipients [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/hla-specific-igd-cd27-double-negative-b-cell-frequency-assessed-by-a-novel-multiplex-bead-based-assay-predicts-rejection-in-kidney-transplant-recipients/. Accessed June 30, 2022.
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