From the Guidelines
Perform comprehensive DSA screening using solid-phase assays like Luminex before transplantation to identify and quantify pre-existing DSAs. This approach is supported by recent studies, including the 2023 consensus report by the Sensitization in Transplantation: Assessment of Risk working group 1, which emphasizes the importance of DSA matching in predicting the risk of antibody-mediated rejection.
Specifics:
- Test recipient's serum against a panel of HLA antigens
- Identify and quantify any pre-existing DSAs
- Set a mean fluorescence intensity (MFI) threshold, typically 1000-3000
- Consider desensitization for recipients with DSAs above the threshold
Additional Information:
- Repeat testing periodically while on the waitlist to monitor for changes in DSA levels
- Perform virtual crossmatch using DSA results before accepting an organ offer to minimize the risk of rejection
- Continue monitoring post-transplant for de novo DSA development to promptly identify and manage any potential issues
The justification for this approach is based on the well-established contribution of anti-HLA donor-specific antibodies (DSAs) to organ rejection and allograft loss, as highlighted in the 2023 study by C. Lefaucheur et al. 1. By identifying pre-existing antibodies against donor HLA antigens, transplant teams can make informed decisions about organ allocation and immunosuppression strategies, ultimately improving graft survival and patient outcomes. This is further supported by the 2024 EASL clinical practice guidelines on liver transplantation, which recommend screening for preformed DSAs in recipients at risk of humoral sensitization 1.
From the Research
Donor-Specific Antigen (DSA) Matching Process
The process for DSA matching involves several steps to determine compatibility between a patient and a donor before solid organ transplantation. The goal is to prevent hyperacute rejection and ensure the best possible outcome for the patient.
- Crossmatching: A final crossmatch is the gold standard for determining compatibility between patient and donor 2. This process involves testing the patient's blood against the donor's blood to check for any reactions.
- DSA Testing: Donor-specific antibody testing is used to identify antibodies that are specific to the donor's HLA antigens 3. This testing can help predict the risk of antibody-mediated rejection.
- Epitope Matching: HLA epitope matching is a more precise method of matching that involves identifying specific regions on the HLA molecule that are recognized by antibodies 4, 5. This approach can help reduce the risk of de novo DSA formation and improve graft survival.
- Monitoring and Removal: Patients with preformed DSA require regular monitoring to track changes in antibody levels and to remove DSA when necessary 6. This monitoring can help prevent antibody-mediated rejection and improve graft survival.
Key Considerations
When performing DSA matching, several factors must be considered, including:
- HLA Compatibility: The compatibility of the donor's and patient's HLA antigens is crucial in determining the risk of rejection 2, 4.
- Antibody Specificity: The specificity of the patient's antibodies to the donor's HLA antigens must be determined to predict the risk of rejection 3, 5.
- Epitope Mismatches: The presence of epitope mismatches between the donor and patient can increase the risk of rejection 4, 5.
- DSA Levels: The levels of DSA in the patient's blood must be monitored regularly to track changes and adjust treatment as needed 6.