Researchers discovered that red blood cells serve an essential function in the immune system through the development of DNA-binding capabilities

Nov, 2021 - By WMR

Researchers have long recognized that RBCs, which are responsible for transporting oxygen to the body, make contact with the immune response, but until recently, they didn't realize whether they directly influenced inflammation.

A new study shows that red blood cells act as important immune sensors by binding cell-free DNA, known as nucleic acid, occurring in the body's circulation during COVID-19 and sepsis, and this DNA-binding capacity stimulates their discharge from circulation, driving inflammatory response and anemia during serious disease and acting a much bigger role in the immune response than previously believed. Anemia is a widespread condition that affects almost a quarter of the global population.

TLRs are a family of proteins that act an important role in the immune response by activating immunological responses such as cytokine production. The RBCs of 100 COVID-19 patients and 50 sepsis patients were studied in this research, and it was discovered that during these diseases, red blood cells express an elevated number of the particular TLR protein TLR9 on its surfaces. The findings revealed that RBCs lose their natural shape when they attach too much inflammation-inducing nucleic acid, causing the body to lose recognition of them. This causes immune cells known as macrophages to eat them, removing them from circulation. Once this happens, the immune system in undamaged organs becomes activated, causing inflammation. This molecular breakthrough paves the way for research into how to suppress these specific receptors and develop targeted therapeutics for viral diseases, autoimmune diseases, and a slew of other inflammatory conditions linked to acute anemia.

The discovery of a DNA-binding protein could have ramifications for research into the use of red blood cells in diagnosis. For instance, if a physician might collect RBCs from a patient with pneumonia, sequence the nucleic acid absorbed from the illness, and identify the exact bacteria to better select which drug to provide. Researchers are investigating if this is a viable technique for diagnosing infection in critically ill individuals, as well as whether this DNA-binding process by RBCs is a common cause of parasite anemia.