Date: Monday, May 4, 2015
Session Time: 5:30pm-6:30pm
Presentation Time: 5:30pm-6:30pm
Location: Exhibit Hall E
Background: The use of single antigen beads assay (SAFB) for the detection of anti-HLA antibodies (Abs) may reveal the presence of Abs in individuals without prior sensitization events. It is suggested that many reactions detected by this assay are actually "false positives", possibly arising due to the binding of Abs to denatured HLA molecules on assay. However, it has been already demonstrated the association of these Abs with antibody-mediated rejection (AMR).
Purpose: To evaluate the presence and logitudinal changes of preformed DSA levels among patients without previous alloimmunization events and to correlate these findings with AMR episodes during the first year post-transplant.
Methods: The sera were obtained pre-transplant and at 14, 30, 90, 180 and 365 days post-transplant. All serum samples were tested for DSA using the LABScreen® SAFB and a MFI (mean fluorescence intensity)>1000 was considered to be positive. Immunization events: pregnancy, blood transfusion and previous transplant were recorded at the patient admission to the hospital.
Results: Seventy-one patients (45 men and 26 women) were included in this study. 50,7% of the patients had blood transfusion antecedents, 4,2% had previous transplant and 69,2% of the female patients had at least one pregnancy event. Preformed DSA was present in 15 patients. AMR occurred in 2 patients. Both patients were female with history of pregnancy. Preformed anti-HLA Abs were present in 10 patients without previous alloimmunization events identifiable. Among these patients, 4 had anti-HLA Ab classified as DSA, one patitent with MFI > 5000, and 3 of these patients had persistent detectable DSA during the study, with MFI values similar to the initial ones, possibly indicating false positive reactions. All of these patients were free of AMR episodes.
Conclusion: A combination of antibody screening tests and history of immunization events is of pivotal importance for the correctness of evaluating the immunological risks of potential recipients. The prospective monitoring of these Abs may help identify false positive reactions.
To cite this abstract in AMA style:Glasberg D, Carvalho DMonteirode, Matuck T, Fabricio-Silva G, Barbosa M, Borela A, Christiani L, Malta R, Porto L. Evaluation of Preformed Anti-HLA Antibody of "Unknown Origin" after Kidney Transplant in a Brazilian Center [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/evaluation-of-preformed-anti-hla-antibody-of-unknown-origin-after-kidney-transplant-in-a-brazilian-center/. Accessed July 30, 2021.
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