Guards! Guards! How innate lymphoid cells ensure local law and order

This special issue of the Biomedical Journal is dedicated to the latest official recruits in the field of immunology: innate lymphoid cells, the tissue-resident sentinels and first responders to damage or invasion. Subsequently, we consider extracellular vesicle release during bacterial infection, how immunomodulation can avoid compromising Mycobacterium tuberculosis clearance, and how innate immunity jeopardises the organism during rheumatoid arthritis. Moreover, we ponder over the predictive value of cardiac troponin in influenza, the virtues of cashew nuts and bilirubin, as well as holes in the heart. Finally, we learn that mandibular movement during swallowing increases with the vertical dimension of occlusion, and that early controlled relaxation incisions restore the blood supply to the extremities in harlequin ichthyosis neonates.