Alemtuzumab Associated Listeria Monocytogenes Meningitis

Purpose Describe a case of Listeria monocytogenes meningitis following initiation of alemtuzumab therapy in a patient diagnosed with relapsing–remitting multiple sclerosis (RRMS). Summary A 44-year-old female presented with headache and fever seven days after completion of an initial course of alemtuzumab for the treatment of RRMS. Blood cultures were positive for gram-positive bacilli. A lumbar puncture revealed cell counts, consistent with bacterial meningitis and magnetic resonance imaging (MRI) revealed abnormal signal enhancement of the left cingulate gyrus. Vancomycin, ceftriaxone, and ampicillin were initiated empirically. Both blood and cerebrospinal fluid cultures resulted positive for Listeria monocytogenes. Antibiotics were narrowed to ampicillin for a treatment duration of 21 days, after which symptoms resolved and she was transitioned home. Alemtuzumab is a CD52-directed cytolytic monoclonal antibody that has previously been implicated in association with cases of Listeria monocytogenes meningitis in other countries. Based on its mechanism of action, previous association, and positive temporal relationship, we hypothesize that alemtuzumab played a substantial role in the development of L. monocytogenes meningitis in this patient. Conclusion To our knowledge, this is the first reported case of alemtuzumab associated Listeria meningitis in the United States. This case highlights the severe lymphopenia associated with alemtuzumab therapy and risk of subsequent opportunistic infection. Heightened vigilance in counseling and monitoring of dietary restrictions is critical both prior to and during alemtuzumab therapy. A greater role of prophylactic antibiotics may also be warranted.