CD8+ T cell cytotoxicity mediates pathology in the skin by inflammasome activation and IL-1β production.

• Main Authors: Fernanda O Novais, Augusto M Carvalho, Megan L Clark, Lucas P Carvalho, Daniel P Beiting, Igor E Brodsky, Edgar M Carvalho, Phillip Scott
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2017-02-01
• Series: PLoS Pathogens
• Online Access: https://doi.org/10.1371/journal.ppat.1006196

Deregulated CD8+ T cell cytotoxicity plays a central role in enhancing disease severity in several conditions. However, we have little understanding of the mechanisms by which immunopathology develops as a consequence of cytotoxicity. Using murine models of inflammation induced by the protozoan parasite leishmania, and data obtained from patients with cutaneous leishmaniasis, we uncovered a previously unrecognized role for NLRP3 inflammasome activation and IL-1β release as a detrimental consequence of CD8+ T cell-mediated cytotoxicity, ultimately resulting in chronic inflammation. Critically, pharmacological blockade of NLRP3 or IL-1β significantly ameliorated the CD8+ T cell-driven immunopathology in leishmania-infected mice. Confirming the relevance of these findings to human leishmaniasis, blockade of the NLRP3 inflammasome in skin biopsies from leishmania-infected patients prevented IL-1β release. Thus, these studies link CD8+ T cell cytotoxicity with inflammasome activation and reveal novel avenues of treatment for cutaneous leishmaniasis, as well as other of diseases where CD8+ T cell-mediated cytotoxicity induces pathology.