Thrombotic microangiopathy caused by oral contraceptives in a kidney transplant recipient

Thrombotic microangiopathy (TMA) after kidney transplantation has various aetiologies, including acute antibody-mediated rejection, bacterial or viral infection and immunosuppressive drugs, particularly calcineurin inhibitors. We present the case of a 28-year-old woman who developed TMA 30 months after the transplantation of an ABO-incompatible kidney from a living unrelated donor. The patient developed a sudden onset of allograft renal dysfunction and became uremic. She was transferred to our institution from a community hospital with strongly suspected acute allograft rejection. Intensive treatments for both T- and B-cell mediated acute rejection, including steroid pulse therapy, double-filtration plasmapheresis, antithymocyte globulin (1.5 mg/kg × 14 days) and rituximab (100 mg), were initiated during haemodialysis. However, her renal allograft function did not improve. Histopathological analysis 8 days after the treatment indicated TMA, despite the absence of apparent acute T-cell- or acute antibody-mediated rejection. There were no symptoms of infectious diseases, such as intestinal haemorrhagic colitis or viral infection. We concluded that the use of oral contraceptives, which had been initiated 3 weeks before TMA onset for the treatment of irregular vaginal bleeding, was the aetiologic agent.