Aim. Antibody mediated rejection (AMR) represents a risk for graft loss, and the presence of circulating donor-specific antibody (cDSA) is a major criterion for AMR diagnosis. However, identification of cDSA can be challenging. The aim of the present study was to evaluate anti-HLA donor-specific antibody eluted (eDSA) from AMR-triggered allograft biopsies.

Methods. 90 core fine needle biopsies were obtained in 38 transplant patients with biopsy-proven AMR: 28 kidney, three kidney-pancreas, three liver, three liver-kidney and one heart allografts. Core biopsy weight ranged from 0.003g to 0.008g, average 0.005 grams/core. Biopsy eluates were obtained by the acidic method and were further tested for eDSA by single-antigen microbead array, in parallel with matched serum samples, to identify cDSA.

Results. We were able identify eDSA in significantly higher number of patients (23/38, 61%), while cDSA was identified in only 13/38 (34%, p=0.019). The eDSA specificity included HLA-A, -B, -DRB1, -DRB3/4/5, -DQA, -DQB, and DPB1 loci. 11 patients exhibited both eDSA and cDSA, 12 patients were eDSA+ve/cDSA-ve, two patients were eDSA-ve/cDSA+ve, and 13 patients were eDSA-ve/cDSA-ve. ). Of note, 9/13 eDSA-ve/cDSA-ve patients tested positive for circulating anti-angiotensin receptor 1 antibody. While cDSA were associated with eDSA (p = 0.03), a significant proportion of cases had eDSA but not cDSA (12/38, 31%). Furthermore, 6/11 eDSA+ve/cDSA+ve patients exhibited additional specificities in eDSA versus cDSA. In patients with combined liver and kidney allografts, we noted significantly higher MFI values in liver versus kidney biopsy cores (3 to 10 times).

Table 1. Eluted and circulating HLA-specific DSA

Conclusions. Anti-HLA donor-specific antibody identification in eluates from allograft biopsy was almost double than circulating DSA identification. This approach might represent a useful laboratory support for post-transplant AMR monitoring, even in cases without circulating DSA.

CITATION INFORMATION: Girnita A., Portwood E., Brailey P., Cuffy M., Cardi M., Paterno F., Diwan T., Shah S., Govil A., Alloway R., Woodle E. Eluates from Fine-Needle Allograft Biopsy Increase Donor-Specific Antibody Identification in Antibody Mediated Rejection Am J Transplant. 2017;17 (suppl 3).

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