Molecular assemblages, called ASC specks, formed inside macrophage immune cells perpetuate inflammation by being ‘eaten’ by other macrophages according to two independent papers published online this week in Nature Immunology.
Interfering with the release of ASC specks, or preventing their uptake by other macrophages, may serve to dampen harmful inflammation and prevent it from spreading widely through the body, as seen in pneumonia and spontaneous human autoinflammatory disease.
Macrophages are key immune cells involved in clearing tissue debris and driving inflammation. Studies from Eicke Latz, Pablo Pelegrin and their respective colleagues show that macrophages die soon after ASC specks assemble and these cells then release their contents into the surrounding medium. ASC specks released during macrophage cell death not only continue to trigger inflammation outside of the cell, they can also be taken up by other unstimulated macrophages and ‘force’ them to initiate an inflammatory response. This release of ASC specks can therefore result in otherwise localized inflammation to ripple outward and have much more wide-spread effects.