De novo post-transplant thrombotic microangiopathy localized only to the graft in autosomal dominant polycystic kidney disease with thrombophilia

Introduction: thrombotic microangiopathy (tma) is a serious complication of renal transplantation and is mostly related to the prothrombotic effect of calcineurin inhibitors (cnis). a subset of tma (29%-38%) is localized only to the graft.case 1: a young woman suffering from autosomal dominant polycystic kidney disease (adpkd) underwent kidney transplant. after 2 months, she showed slow renal deterioration (serum creatinine from 1.9 to 3.1 mg/dl), without hematological signs of hemolytic-uremic syndrome (hus); only ldh enzyme transient increase was detected. renal biopsy showed tma: temporary withdraw of tacrolimus and plasmapheresis was performed. the renal function recovered (serum creatinine 1.9 mg/dl). from screening for thrombophilia, we found a mutation of the leiden factor v gene.case 2: a man affected by adpkd underwent kidney transplantation, with delay graft function; first biopsy showed acute tubular necrosis, but a second biopsy revealed tma, while no altered hematological parameters of hus was detected. we observed only a slight increase of lactate dehydrogenase (ldh) levels. the tacrolimus was halved and plasmapheresis was performed: ldh levels normalized within 10 days and renal function improved (serum creatinine from 9 to 2.9 mg/dl). we found a mutation of the prothrombin gene. only a renal biopsy clarifies the diagnosis of tma, but it is necessary to pay attention to light increasing level of ldh.conclusion: prothrombotic effect of cnis and mtor inhibitor, mutation of genes encoding factor h or i, anticardiolipin antibodies, vascular rejection, cytomegalovirus infection are proposed to trigger tma; we detected mutations of factor ii and leiden factor v, as facilitating conditions for tma in patients affected by adpkd.