Late post-transplant recurrence of an anti-myeloperoxydase antibody-associated vasculitis in a former double-positive patient: a case report.

Post-transplant anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) recurrence on the allograft is rare and, to our knowledge, has never been described in the situation of a previous double-positive vasculitis with both ANCA and anti-glomerular basement membrane (GBM) antibodies. We report an unusual case of anti-myeloperoxydase (MPO) antibody-associated vasculitis recurrence occurring 14 years after kidney transplantation following a double-positive anti-GBM and anti-MPO glomerulonephritis. The transplant induction regimen consisted of anti-thymocyte globulin, and initial maintenance therapy associated tacrolimus, mycophenolate mofetil, and corticosteroids. Mycophenolate mofetil was discontinued 4 months after transplantation due to persistent leukopenia, and tacrolimus was maintained along with corticosteroids. At 14 years post-transplantation, the patient presented with diffuse alveolar hemorrhage, acute kidney injury stage 1 of Kidney Disease Improving Global Outcomes, proteinuria, microhematuria, serous otitis media and anti-MPO antibodies resurgence, without detectable anti-GBM antibodies. A kidney allograft biopsy was performed and showed rare active crescents with severe chronic injuries. This pulmonary and renal involvement was attributed to an anti-MPO antibody-associated vasculitis recurrence. The induction treatment of the relapse consisted of methylprednisolone at 5 mg/kg and rituximab at 375 mg/m