Alemtuzumab in the reversal of encephalopathy associated with hypereosinophilic syndrome

Abstract

A 63-year-old woman who had a 1-year history of FIP1L1PDGFRa-negative hypereosinophilic syndrome, presented with the sudden onset of ataxia and strength loss in lower extremities, spatial disorientation, and neglect of the left side of her body. She had an eosinophil count of 161AE8 · 10/l. Brain magnetic resonance imaging (MRI) with fluid-attenuated inversion recovery (FLAIR) sequence showed extensive bilateral and diffuse abnormalities situated in watershed regions (left panel). Therapy with corticosteroids, hydroxycarbamide, interferon-a (5 000 000 units/day), and low-dose subcutaneous cytarabine (20 mg/day) was effective in reducing her eosinophil count, which stabilized at 40 · 10/l. Neurological symptoms were also stable. Four months after this presentation, the patient was readmitted with significant worsening of her neurological symptoms, with cerebellar ataxia and urinary incontinence. The patient was treated with subcutaneous alemtuzumab at a dose of 30 mg/week. She had an excellent response, with the eosinophil count stabilizing at 5 · 10/l after three doses, achieving a partial haematological response. A 6-month MRI follow-up showed decrease in the size of the lesions (right panel).