Khan S, Vaisman A, Hota SS, et al. - Investigators assessed the susceptibility of Listeria in individuals with multiple myeloma receiving daratumumab-based therapy. Whilst cluster of differentiation (CD) 38 (CD38) was highly expressed via myeloma cells, it was also expressed through activated macrophages, and seemed to play a significant role in defense against Listeria, restraining the infection of the macrophage cytoplasm through phagocytosed bacilli and limiting macrophage-based dissemination. CD38 inactivation resulted into a marked susceptibility to Listeria monocytogenes in mice. Since CD38 was also induced on human macrophages, identical mechanisms may underlie human Listeria protection.