BACKGROUND AND AIMS: Preexisting donor specific antibodies (DSA) cause acute antibody mediated rejection (AMR), which can be avoided during pre-transplant work up. Diagnosis and management of AMR post-transplant remains a challenge in heart transplantation. Currently, the presence of de novo DSA is considered as an important indicator for AMR, but cardiac biopsy is still necessary for final diagnosis. The current study aimed to determine the relationship between DSA, third-party HLA antibodies, and AMR.

PATIENTS AND METHODS: Patients who received a heart transplant at the University Chicago Medicine from January 2007 to December 2011, a total of 120 patients, with at least 5 five-year follow-up, were included in this study. Five patients were excluded due to the lack of pathological diagnosis or HLA antibody testing results. 115 patients were included for data extraction including general information, AMR, pre- and post-panel reactive antibody (PRA), and pre-and post-DSA. AMR was diagnosed by positive C4d immunochemistry or immunofluorescence staining. Positive PRA was defined as >5% by solid phase assay. Presence of DSA was determined by Luminex single antigen bead assay.

RESULTS: AMR was present in 13 patients (11.3%). Of these, two patients (15.4%) had a positive pre-transplant-(TX) PRA, but none of them had pre-TX-DSA. 11 patients (84.6%) showed a positive post-TX-PRA, and de novo DSA were detected in 8 patients (72.7%). Positive pre-PRA was identified in 25 patients (21.8%) and none of them had pre-TX-DSA. Positive post-TX-PRA was found in 44 patients (38.3%) and DSA was detected in 14 of them (31.8%). 8 patients with DSA showed AMR, and 6 of them (75%) had a cumulative MFI >15, 000. In contrast, among the 6 patients with DSA who did not develop AMR, only 2 of them (33.3%) had a MFI >15,000.

CONCLUSIONS: In heart transplantation, positive post-TX-PRA, but not pre-TX-PRA, is associated with AMR. DSA is present in most, but not all, AMR patients, suggesting that HLA may not be the sole targets of pathologic antibodies. When anti-HLA DSA are present, however, the strength of DSA may be an important predictor of AMR diagnosis.

*PM II and JJX equally contributed to this work.

CITATION INFORMATION: McMullen II P, Xin J, Brown N, Upchurch R, Weidner J, Fedson S, Husain A, Marino S. Antibody Mediated Rejection and Donor Specific Antibodies in Heart Transplant Patients: Single Center Experience. Am J Transplant. 2017;17 (suppl 3).

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