Interleukin-3 amplifies acute inflammation and is a potential therapeutic target in sepsis

A new therapeutic target for sepsis Infections can sometimes unleash powerful immune responses that careen out of control, leading to sepsis, organ failure, and death. Although antibiotics can help to quash the infection, sepsis patients also need therapies that will rein in the immune response. Weber et al. now identify one potential target, the secreted protein interleukin-3 (IL-3) (see the Perspective by Hotchkiss). In sepsis patients, higher serum concentrations of IL-3 were correlated with higher rates of mortality. In septic mice, IL-3 caused the immune system to produce large amounts of cells called monocytes and neutrophils, which secrete highly inflammatory proteins. Blocking IL-3 protected mice from sepsis-induced death. Science , this issue p. 1260 ; see also p. 1201