NIH scientists discover how DNA fragments can trigger inflammation in sickle cell disease Scanning electron microscopy image of mitochondrial bundles in several sickle cell red blood cells, showing evidence that circulating red blood cells from people with sickle cell disease abnormally retain mitochondria. Swee Lay Thein, NHLBI Researchers have discovered that DNA from the mitochondria - the cell’s “powerhouses” - acts as a danger signal in the body and triggers inflammation in people with sickle cell disease. A better understanding of mitochondrial DNA, long known to circulate in human blood, may provide vital insight into how to stop the underlying chronic inflammation that marks this inherited red blood cell disorder. It could also lead to new ways to reduce the pain crises suffered by people living with the life-threatening disease.