Lung Transplantation Outcomes after Crossing Low Level Donor Specific Antibodies without Augmented Immunosuppression

Abstract

<h3>Purpose</h3> Lung transplant recipients with pre-transplant donor specific antibodies (DSA) are often treated with augmented immunosuppression. It is unknown whether some DSA can be safely crossed without additional therapies. We implemented a protocol allowing transplant when crossing select low level DSA (defined as mean fluorescence intensity (MFI) 1000-5000) without planned augmented immunosuppression. <h3>Methods</h3> This was a single center retrospective cohort study between 4/1/2015-8/31/2020. All recipients received solumedrol and basiliximab induction without desensitization. Presence of low level pre-transplant DSA was recorded. All post-transplant DSA was monitored within 14 days of transplant and then at routine intervals. The primary study outcomes were overall survival, definite CLAD≥1-free survival, and definite antibody mediated rejection (AMR), all defined according to ISHLT consensus guidelines. <h3>Results</h3> Of the 453 recipients, 36 (7.9%) had a low-level pre-transplant DSA crossed at transplant (Table 1). 13 had Class I antibodies and 26 had Class II. The median historical DSA MFI was 1800 (IQR 1300-2400) and the median most recent MFI was 1200 (IQR 950-2000). Among recipients where pre-transplant DSA was crossed, 17 (47.2%) had persistent post-transplant DSA with a median peak MFI of 7400. Class II antibodies were more likely to be detected post-transplant than Class I (57.7% vs 15.4%, p=0.02). There was no statistical difference in definite AMR in recipients where pre-transplant DSA was and was not crossed (8.3% vs 3.1%, p=0.11). With a median follow-up time of 2.4 years, there were no differences in adjusted overall survival (HR=1.14, 95% CI=0.57-2.32, p=0.71) or CLAD≥1-free survival (HR=0.82, 95% CI=0.44-1.54, p=0.54). <h3>Conclusion</h3> Lung transplantation in the presence of low level DSA without planned augmented immunosuppression was not associated with worse overall or CLAD-free intermediate-term survival but may be associated with increased AMR.