Date: Monday, May 4, 2015
Session Time: 2:15pm-3:45pm
Presentation Time: 3:27pm-3:39pm
Location: Room 121-AB
Even though current bead-based multiplex techniques enable an accurate assessment of circulating HLA-specific antibodies, a more comprehensive study of the humoral alloimmune response through the evaluation of circulating HLA-specific memory B cells would allow a better identification of immunized kidney transplant patients, ultimately at increased risk of ABMR.
Here, using a novel IgG B-cell Elispot assay we evaluated the impact of circulating alloreactive memory B cells among kidney transplants recipients and compared it to the presence of circulating HLA-specific antibodies in different clinical settings. For this purpose, both class I and II HLA-immunized and non-immunized patients on the waiting list for kidney transplantation as well as patients undergoing ABMR were evaluated at time of event and prior to transplantation.
A broad spectrum of both class I and II alloreactive memory B-cell frequencies was consistently identified in highly HLA-immunized patients in the waiting list for a kidney transplant, whereas none were observed among non immunized individuals. A more stable detection of alloreactive memory B cells was observed when assessed over time as compared to circulating HLA-specific antibodies. Intriguingly, while some HLA-specific antibodies could not be detected using current Luminex platform in some patients, detection of circulating IgG-ASC against the same target HLA antigen revealed persistence of humoral immunization. Moreover, high frequencies of alloreactive memory B cells were also observed in kidney transplant patients undergoing acute ABMR at the time of rejection and prior to transplantation. Of note, the higher HLA-specific memory B-cell immune response the more severe ABMR was observed.
Assessment of donor-specific alloreactive memory B-cell frequencies may be of relevance to improve patient alloimmune-risk stratification, and provides new insight into the mechanisms of the adaptive humoral alloimmune response taking place after organ transplantation.
To cite this abstract in AMA style:Lúcia M, Luque S, Crespo E, Cruzado J, Melilli E, Martorell J, Torras J, Gil-Vernet S, Grinyo J, Bestard O. Assessment of Circulating HLA-Specific Alloreactive Memory B Cells Reveals Surreptitious Immunized Kidney Transplant Recipients at High Risk of Antibody-Mediated Rejection [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/assessment-of-circulating-hla-specific-alloreactive-memory-b-cells-reveals-surreptitious-immunized-kidney-transplant-recipients-at-high-risk-of-antibody-mediated-rejection/. Accessed January 19, 2021.
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