Epitope cluster analysis for donor-specific antibody identification in eluates from fine-needle allograft biopsy

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• 作者：Alin Girnita^a ; Elizabeth Portwood^b ; Paul Brailey^b ; Madison Cuffy^a ; Andrei Tica^c ; Flavio Paterno^a ; Tayyab Diwan^a ; Shimul Shah^a ; Gautham Mogilishetty^a ; Michael Cardi^d ; Amit Govil^a ; Rita R. Alloway^a ; E. Steve Woodle^a
• 刊名：Human Immunology
• 出版年：2015
• 出版时间：October 2015
• 年：2015
• 卷：76
• 期：supp_S
• 页码：125-126
• 全文大小：548 K

文摘

The aim of the present study was to evaluate anti-HLA antibody eluted from fine needle allograft biopsies.

Methods

Two tissue-pieces and ten core fine needle biopsies were obtained in 9 transplant patients: 7 with biopsy-proven C4d+ antibody mediated rejection (ABMR), and two without rejection; 6 kidneys, 3 livers and one combined kidney–liver transplants. Tissue pieces weight was 0.33 g and 2.24 g, respectively. The weight of core biopsy ranged from 0.004 g to 0.008 g, average 0.006 g/core. Elution was performed by an acidic method, and then eluates were tested for donor-specific anti-HLA antibody (eDSA) by Luminex in parallel with serum samples. Cluster analysis considered both theoretical and adsorption/elution proved epitopes.

Results

We identified eDSA in all ABMR patients (6/7 with circulating DSA), and in none of controls. There was a linear correlation between antibody strength (MFI) and tissue weight (figure), both for class I, and class II DSAs. However, since the MFI average in eluates was only in the range of hundreds, epitope clustering was the tool for eDSA identification. We noted higher MFI in liver versus kidney biopsy cores (>80% class I, >75% class II). The epitope distribution of DSA eluted from biopsy is summarized in the table and were previously described by adsorption/elution cell lines (El-Awar et al). In contrast, circulating antibodies exhibited combinations of theoretical and elution-proved epitope patterns.

Conclusions

Given the low amount of HLA-specific antibody eluted from fine-needle core allograft biopsy, epitope cluster analysis can be used for antibody identification, even in ABMR cases where circulating DSA cannot be documented.