May 2016: Study shows how compounds produced by the body’s immune system help to dampen inflammation and prevent damage to healthy tissues Arthritis and other inflammatory conditions could be helped by new insights into how the immune response is switched off. Scientists led by Dr Mohini Gray have discovered how compounds produced by the body’s immune system help to dampen inflammation and prevent damage to healthy tissues. Their findings suggest that therapies based on these compounds could help to treat rheumatoid arthritis, which occurs when the immune system attacks the joints, causing pain and swelling. The research could also lead to new treatments for sepsis, where a body-wide immune response causes life-threatening tissue damage. The compounds called alpha defensins are part of the body’s first line of defence against infection. They help to stop bacteria and other infectious agents from reproducing. Studies have suggested that the compounds may also act on cells of the immune system to prevent excessive inflammation but until now it was not clear how the process works. In a study involving human cells, researchers at the University of Edinburgh have shown that alpha defensins are released by immune cells called neutrophils when they die. The alpha defensins are then taken up by other immune cells called macrophages. The team found that the compounds prevent macrophages from producing messenger molecules called cytokines, which drive inflammation. The overall effect is to limit excessive inflammation, restricting damage to healthy tissues without compromising the body’s ability to clear the infection. These findings could lead to new treatments for chronic inflammatory disorders including rheumatoid arthritis. Such therapies could even prevent the condition from flaring-up in the first place, the team predicts. The study, funded by the Medical Research Council and Arthritis UK, is published in the journal Proceedings of the National Academy of Sciences. Publication date 01 Jul, 2016
