Post-injury immunosuppression and secondary infections are caused by an AIM2 inflammasome-driven signaling cascade.
Immunity. 2021 Mar 1:S1074-7613(21)00070-4. doi: 10.1016/j.immuni.2021.02.004. Epub ahead of print. PMID: 33667383.
|Authors/Editors:||Roth S, Cao J, Singh V, Tiedt S, Hundeshagen G, Li T, Boehme JD, Chauhan D, Zhu J, Ricci A, Gorka O, Asare Y, Yang J, Lopez MS, Rehberg M, Bruder D, Zhang S, Groß O, Dichgans M, Hornung V, Liesz A.|
Loss of lymphocytes, particularly T cell apoptosis, is a central pathological event after severe tissue injury that is associated with increased susceptibility for life-threatening infections. The precise immunological mechanisms leading to T cell death after acute injury are largely unknown. Here, we identified a monocyte-T cell interaction driving bystander cell death of T cells in ischemic stroke and burn injury. Specifically, we found that stroke induced a FasL-expressing monocyte population, which led to extrinsic T cell apoptosis. This phenomenon was driven by AIM2 inflammasome-dependent interleukin-1β (IL-1β) secretion after sensing cell-free DNA. Pharmacological inhibition of this pathway improved T cell survival and reduced post-stroke bacterial infections. As such, this study describes inflammasome-dependent monocyte activation as a previously unstudied cause of T cell death after injury and challenges the current paradigms of post-injury lymphopenia.