Risk mitigation of autoimmune encephalitis recurrence in the setting of immune-checkpoint inhibitor therapy: a case report

Background

Immune checkpoint inhibitors (ICIs) have transformed cancer therapy but can lead to serious immune‐related adverse events (irAEs), including provocation of autoimmune encephalitis.

Case Report

A middle-aged woman presented with new-onset confusion, memory impairment, epileptic seizures leading to a diagnosis of limbic encephalitis, as supported by objective findings of inflammation on neuroimaging and CSF analysis. Metastatic urothelial carcinoma was discovered during her diagnostic evaluation for limbic encephalitis. Administration of high-dose corticosteroids and plasma exchange achieved neurologic stabilization acutely; however, her malignancy proved challenging to treat.

Case Presentation

Tumor progression prompted a multi-disciplinary plan to trial ICIs despite concern of resultant neurotoxicity. To offset potential iatrogenic neuroinflammation, the patient received maintenance intravenous immunoglobulin (IVIg) 0.4 g/kg ideal body weight biweekly in conjunction with oncologic-directed immunotherapy. Over a six-month follow-up period, the patient maintained neurologic stability without worsening encephalitis. She tolerated the combined IVIg–ICI regimen without infusion reactions or exacerbation of neurologic toxicity.

Conclusion

This case suggests that prophylactic maintenance IVIg may allow for safe administration of ICIs in patients with pre-morbid limbic encephalitis. Prospective studies with a larger sample size are needed to validate IVIg as a strategy to prevent provocation of pre-morbid limbic encephalitis in those requiring oncologic-directed immunotherapy.