Kidney transplantation in congenital thrombotic thrombocytopaenic purpura: using recombinant ADAMTS13 to balance relapse and rejection.

Congenital thrombotic thrombocytopaenic purpura (cTTP) is an extremely rare disease, and kidney transplantation in this population is even rarer. Finding an appropriate immunosuppressive regimen in cTTP transplant recipients can be challenging, as calcineurin inhibitors are associated with an increased risk of thrombotic microangiopathy (TMA), whereas prophylactic plasma exchange reduces the blood concentrations of mycophenolic acid and belatacept. We discuss a kidney allograft recipient with cTTP having repeated episodes of T-cell-mediated rejection with systemic TMA. Changes to his immunosuppressive regimen and intensification of plasma exchange therapy terminated TMA temporarily but failed to prevent its recurrence. Ultimately, he was treated with recombinant a disintegrin and metalloproteinase with a thrombospondin type one motif, member 13 (ADAMTS13) infusions, halting TMA and preventing future episodes. This is the first case of prophylaxis with recombinant ADAMTS13 in a kidney allograft recipient, illustrating its potential benefit over plasma exchange by assuring therapeutic immunosuppressants' concentrations and preventing both rejection and TMA-induced graft injury.