Testing Intervals
A retrospective Flow (and potentially CDC) crossmatch should be carried out and a Luminex SAB test on the day of transplant sample. In addition, post-transplant HLA antibody testing by Luminex is generally carried out at day 14 and 28 at a minimum and 3, 6, 9 and 12 monthly thereafter and al
so following any signs of acute rejection.
Suspected AMR post heart transplant
AMR is indicated in the presence of circulating DSA, graft dysfunction and C4d positive biopsy. Post-transplant HLA antibody testing is carried out at regular intervals, at the time of protocol biopsy and at the time of suspected rejection to aid post-transplant management.
If DSA is detected and C4d is positive then patient need to be treated for HLA antibody mediated rejection. If the Luminex screen and SAB are Neg. this needs to be confirmed/repeated, ensuring testing has been done with adsorb and with EDTA. If confirmed the C4d is likely due to non-HLA antibodies. Anti-endothelial, anti-vimentin and anti ABO and other non-HLA antibodies have been shown to be implicated in acute rejection in heart transplant patients. If non-HLA antibodies are present this can be treated by changes in the immunosuppression regime.
Heart Transplant Follow Up
If a patient has not had a HLA antibody test for over a year, a new sample needs to be requested for follow up antibody investigation. The results need to be reviewed alongside all the HLA antibody tests since the transplant and including the transplant sample itself and the DSA levels tabulated and graphed to show changes in the DSA level over time.
Clinicians might consider intervention if DSA levels are over 5000 MFI. Interventions that might be considered include starting on rituximab and IVIg and monitoring antibody levels. If antibody levels do not come down or graft dysfunction is detected, then plasmapheresis or immunoadsorption and possibly Bortezimab may also be considered.
Where plasmapheresis is being considered, the H&I laboratory can undertakes Luminex SAB titre tests to predict the number of plasmapheresis or immunoadsorption rounds that may be required and if these proceed, pre and post plasmapheresis/immunoadsorption Luminex SAB testing to determine if DSA MFI levels are reducing.
Lung Transplant Follow Up
Similar to a heart transplant follow up, if a patient has not had a HLA antibody test for over a year, a new sample needs to be requested for follow up antibody investigation. The results need to be reviewed alongside all the HLA antibody tests since the transplant and including the transplant sample itself and the DSA levels tabulated and graphed to show changes in the DSA level over time.
Clinicians might consider intervention if DSA levels are over 5000 MFI. Interventions that might be considered include starting on rituximab and IVIg and monitoring antibody levels. If antibody levels do not come down or graft dysfunction is detected, then plasmapheresis or immunoadsorption and possibly Bortezimab may also be considered.
Where plasmapheresis is being considered, the H&I laboratory can undertakes Luminex SAB titre tests to predict the number of plasmapheresis or immunoadsorption rounds that may be required and if these proceed, pre and post plasmapheresis/immunoadsorption Luminex SAB testing to determine if DSA MFI levels are reducing.