Date: Saturday, April 29, 2017
Session Time: 5:30pm-7:30pm
Presentation Time: 5:30pm-7:30pm
Location: Hall D1
Chronic (c)ABMR is a main cause of immune-mediated kidney allograft loss. For its diagnosis, specific histological lesions together with presence of circulating donor-specific alloantibodies (DSA) must be identified. However, a significant number of patients showing such specific histological lesions do not display detectable circulating DSA using most sensitive immune assays thus, impeding a consistent diagnosis of immune-mediated cABMR driven by anti-HLA antibodies. Importantly, circulating donor-specific (d-sp) memory B cells (mBC) have been shown to be detectable, regardless the presence of circulating DSA and be associated to ABMR in kidney transplant (KT) patients.
Methods: In a cross-sectional analysis of 78 KT patients showing different histological phenotypes following Banff'13 classification: i) aABMR with DSA (n=16), ii) cABMR with DSA (n=22), iii) cABMR without DSA (n=19), iv) IFTA lesions without inflammation and no DSA (n=8) and v) normal parenchyma (STA) (n=13); presence of d-sp mBc frequencies using an HLA-sp B-cell ELISPOT assay as well as different B-cell and T follicular helper subsets in peripheral blood were assessed and compared between groups. Supernatants of d-sp mBc cultures were also evaluated and correlated with circulating DSA.
Results: Patients with cABMR with DSA and those with cABMR without DSA showed similar d-sp mBC frequencies (0.22±0.26 and 0.27±0.25, p=NS) but significantly higher than STA patients (0.04±0.05, p=0.004 and p=0.001), whereas only 2 IFTA and none of STA individuals showed detectable d-sp mBc frequencies. Supernatants of stimulated mBC cultures illustrated the lower Ab production of mBC in cABMR patients compared to aABMR individuals, which was demonstrated by the higher detection sensitivity of the B–cell ELISPOT assay. No differences were detected in the numbers of the different B-cell subsets and TFH subsets in peripheral blood between groups.
Conclusion: Assessment of circulating mBC frequencies may be useful to discriminate the immune effector mechanism of different kidney allograft injuries, in addition to circulating DSA.
CITATION INFORMATION: Luque S, Lúcia M, Jarque M, Crespo E, Melilli E, Martorell J, Cruzado J, Torras J, Grinyó J, Bestard O. Circulating Donor-Specific Memory B Cells (mBc) Discriminates Kidney Transplant Patients with Histological Lesions of ABMR in Absence of Circulating DSA. Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:Luque S, Lúcia M, Jarque M, Crespo E, Melilli E, Martorell J, Cruzado J, Torras J, Grinyó J, Bestard O. Circulating Donor-Specific Memory B Cells (mBc) Discriminates Kidney Transplant Patients with Histological Lesions of ABMR in Absence of Circulating DSA. [abstract]. Am J Transplant. 2017; 17 (suppl 3). https://atcmeetingabstracts.com/abstract/circulating-donor-specific-memory-b-cells-mbc-discriminates-kidney-transplant-patients-with-histological-lesions-of-abmr-in-absence-of-circulating-dsa/. Accessed October 20, 2020.
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