Proc. Natl. Acad. Sci. USA https://doi.org/10.1073/pnas.1711950115 (16 January 2018)

Mitochondrial DNA (mtDNA) released from myeloid cells acts as a damage-associated molecular pattern that drives inflammation. In the Proceedings of the National Academy of Sciences USA, Rosén and colleagues demonstrate that mtDNA can also be released by lymphocytes (T cells, B cells and natural killer cells) specifically in response to the oligonucleotide CpG-C but not in response to inflammatory cytokines or lipopolysaccharide. Released mtDNA forms characteristic ‘webs’ that are distinct from neutrophil extracellular traps in their function, structure and mode of release. The release of mtDNA does not require cell death, nor apparently do the mtDNA webs serve a bacteriostatic function, as they lack the antibacterial peptides present in neutrophil extracellular traps. Instead, mtDNA webs can elicit the production of type I interferons and might therefore be involved in certain inflammatory diseases.