[Post colonoscopic Listeria monocytogenes meningitis in a patient with multiple myeloma during daratumumab-based therapy].

A 69-year-old man with an unremarkable medical history presented with asymptomatic pancytopenia and diagnosed with Bence Jones protein-λ multiple myeloma (MM). Despite treatment with various chemotherapeutic regimens, myelosuppressive neutropenia occurred after each successive course; therefore, the treatment was determined to be ineffective and was discontinued. Consequently, one year after the diagnosis, a daratumumab-based therapy was initiated, and the MM was stabilized without clinical or laboratory evidences of myelosuppression. However, 18 months after the daratumumab induction, the patient developed hematochezia. Following an unremarkable lower gastrointestinal endoscopy, he presented fever and disturbed consciousness. Serum laboratory results showed liver dysfunction, and Listeria monocytogenes meningitis was diagnosed by cerebrospinal fluid examination. Empiric antibacterial treatment was administered for 3 weeks, which resolved the symptoms with no permanent neurological deficit.Daratumumab, a CD38 monoclonal antibodies, binds to expressed CD38 on myeloma cells and has an anti-myeloma cytotoxic effect but also binds to CD38 on activated macrophages. Additionally, activated macrophages play an important role in the immune defense of Listeria monocytogenes. Furthermore, inactivation of macrophages may increase the susceptibility to Listeria infection. Therefore, the possibility of infections such as Listeria meningitis should be considered in patients with MM receiving daratumumab-based therapy.