Published in Nature Immunology (March 25, 2012), the study was collaboration between Queen Mary University of London and research teams in the United States. Scientists found that because an older population is more susceptible to chronic inflammatory diseases that produce neutrophil-mediated tissue injury like periodontitis, they closely examined a protein called Del-1. Del-1 works with the immune system to stop white blood cells from attaching and attacking mouth tissue. The defensive properties of Del-1 were revealed as researchers experimented with young and old mice; mice lacking Del-1 exhibited severe gum disease and bone loss in addition to a high amount of white blood cells in the gum tissue, while mice with Del-1 had fewer cases of gum disease and bone loss and a reduced number of white blood cells. Taking these findings into consideration, the study further established that Del-1 tends to decline in individuals as they age. Because this protein is integral to protecting the gums from disease and periodontitis, the lack of Del-1 leaves an individual more vulnerable to oral complications. This opens the door for more research centered on the properties of Del-1 and could establish new ways to better treat gum disease.