Unexpected Seizure Complication Post‐Apheresis in a Young Adult With Sickle Cell Disease: A Case Report

This case report presents a previously unreported grade 4 adverse event in a 23-year-old male with sickle cell disease (SCD) undergoing autologous stem cell collection for gene therapy. About 8 h after the collection of stem cells, the patient experienced a generalized tonic-clonic seizure. Imaging revealed a right temporal infarct, newly identified but determined to be subacute. Common causes such as electrolyte imbalance, a thromboembolic event, and posterior reversible encephalopathy syndrome (PRES) were excluded. Given the temporal relation of seizure occurrence after the apheresis procedure, an adverse event due to apheresis cannot be excluded. Seizure due to apheresis has not been reported before and would be categorized as grade 4 according to the common terminology criteria for adverse events (CTCAE). This case highlights the need to report and collect all adverse events that occur during or after apheresis procedures in SCD patients undergoing gene therapy to better counsel patients on the potential risks and prevention strategies.