Eculizumab to Treat Posterior Reversible Encephalopathy Syndrome Due to Underlying Transplant-Associated Thrombotic Microangiopathy in Patients Receiving Allogeneic Hematopoietic Cell Transplant for Sickle Cell Disease

Pre-existing endothelial dysfunction and vascular injury sustained during allogeneic hematopoietic stem cell transplantation (HCT) increases risk for endothelial injury-related complications like posterior reversible encephalopathy (PRES) and transplant-associated thrombotic microangiopathy (TA-TMA) in patients with sickle cell disease (SCD). Herein, we report two SCD HCT recipients in whom PRES-related symptoms resolved only after eculizumab therapy was initiated for underlying TA-TMA. Case 1 25-year-old male with SCD developed PRES-related seizures and headaches on Day+30 following matched sibling donor bone marrow transplant (BMT) and reduced-intensity conditioning (RIC) with fludarabine/melphalan/alemtuzumab and graft-versus-host disease (GvHD) prophylaxis with tacrolimus and methotrexate (MTX). Symptoms initially resolved after discontinuing tacrolimus. However, on Day+60, he presented with hypertension (HTN), status epilepticus, and right intracranial hemorrhage. Despite adequate HTN control and maximal anti-epileptic therapy, his symptoms persisted. Two weeks later, laboratory testing confirmed TA-TMA. Both PRES and TA-TMA symptoms and signs resolved after five weeks of eculizumab therapy (Figure 1). Case 2 Eight-year-old female with SCD underwent 10/10 matched unrelated BMT following RIC with fludarabine/melphalan/thiotepa/alemtuzumab and MTX/tacrolimus/abatacept for GvHD prophylaxis. She developed altered mental status, seizures, and HTN and Day+74 MRI brain confirmed PRES. Her symptoms also persisted despite tacrolimus cessation and effective HTN control. One week later, laboratory testing confirmed TA-TMA. Complete resolution of neurological symptoms occurred after three weeks of eculizumab therapy. (Figure 2). Conclusion Our cases highlight maintaining a high level of clinical suspicion for TA-TMA in SCD patients presenting with PRES post-HCT and consideration for eculizumab therapy in such patients.