Presensitization revisited: pitfalls of vascular allografts in transplant candidates
A man aged 55 received his first kidney transplant from an HLA-identical sibling in 2010 and was immunosuppressed with steroids and cyclosporine. Luminex screen test was negative in pretransplant sera, but positive (ratio >2.5) 1 year after transplantation. The Luminex single antigen assay then revealed multiple antibodies directed to HLA class I and II molecules. Since no blood transfusions had been performed, the only plausible immunizing event was an arterial interponate from a deceased donor inserted during the transplantation to prolong the donor renal artery. We suspected renal transplant artery stenosis as the patient developed hypertension requiring the addition of a selective alpha-1-receptor blocker to his preexisting regimen of beta-blocker, angiotensin-II-receptor antagonist and loop diuretics. Ultrasound investigations 13 and 19 months post-transplantation indicated moderate proximal renal transplant artery stenosis. A fluorodeoxyglucose (18F)-positron emission tomography (FDG-PET) scan was performed 19 months after transplantation in order to detect inflammation in the renal artery interponate, but the result was negative. Twenty-three months post-transplantation, magnetic resonance imaging confirmed a proximal narrowing of the transplant artery, but no significant stenosis. Taken together with stable graft function at an eGFR of 42, indication for intervention was not found. Three years after transplantation graft function, blood pressure and medication remain unaltered.