Date: Tuesday, June 4, 2019
Session Time: 6:00pm-7:00pm
Presentation Time: 6:00pm-7:00pm
Location: Hall C & D
*Purpose: Decreased antigen expression among blood group A, subtype 2 (A2), donor kidneys allows these kidneys to be considered as universal donor kidneys and under the new Kidney Allocation System to be preferentially transplanted into blood group B recipients. Blood group B and O recipients with low titer pre-transplant anti-A antibodies have been shown to have excellent outcomes after A2-incompatible transplantation. However, post-transplant rebound is common, and to date, no study has examined the correlation between this rebound and likelihood of subclinical antibody mediated rejection (AMR).
*Methods: We report 22 ABO incompatible A2/A2B to B/O transplantations with pre transplant anti-A gel titers ≤ 1:64 and daily post-transplant anti-A gel titer monitoring. Immunosuppression consisted of anti-thymocyte globulin induction, tacrolimus, mycophenolate mofetil and prednisone. No patients received pre-transplant conditioning regimen with plasmapheresis. Anti-A titers were measured at baseline and then daily for 14 days after transplantation.
*Results: Median age at transplantation was 50 years. Pre transplant titers were ≤ 1:64 (range 1:2- 1:64). Recipients were predominantly blood type B (B: 59%; O: 41%), male (64%), black race (55%), and received deceased donor kidneys (55%). Titers declined in all patients immediately after transplant and gradually increased during the first post-transplant week. Median time to rebound was 5 days (range 4-6). Median time to peak in gel titers was 10 days (range 9-12 days). There were 3 patients with biopsy proven Banff AMR (>1: thrombotic microangiopathy, glomerulities, and peritubular capillaritis), and none had graft dysfunction at the time of biopsy. Baseline pre-transplant titers did not correlate with AMR; no patients with a rebound titer < 1:128 developed AMR; and 3 out of 6 patients (50%) with anti-A gel titer rebound to > 1:128 developed AMR (Table 1). All 3 patients with biopsy proven subclinical AMR were treated with plasmapheresis, low-dose IVIg, and anti-C5 antibody. No allografts were lost secondary to AMR.
*Conclusions: Rebound in anti-A gel titer to > 1:128 after an A2-incompatible kidney transplantation should prompt a kidney biopsy even in the absence of graft dysfunction to evaluate for subclinical acute AMR. Prompt and aggressive treatment of subclinical AMR should be considered.
To cite this abstract in AMA style:Kumar V, Williams D, MacLennan P, Mustian M, Orandi B, Williams L, Locke J. Post-Transplant Anti- A Titer >1:128 in A2-Incompatible Kidney Recipients is Associated with Subclinical Antibody Mediated Rejection [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/post-transplant-anti-a-titer-1128-in-a2-incompatible-kidney-recipients-is-associated-with-subclinical-antibody-mediated-rejection/. Accessed April 20, 2021.
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