A natural bleach produced by the body appears to play a key role in marshalling the immune system to fight off infection and heal wounds. US scientists, working on zebrafish, which have similar genes to humans, found a burst of hydrogen peroxide is released following a tissue injury. This seems to be the signal for white blood cells to converge at the site of damage and begin the healing process. The Nature study may help explain conditions such as asthma. Asthma, obstruction in the lungs and some inflammatory gut diseases have all been linked to high levels of white blood cells. Although zebrafish would at first appear to have nothing in common with humans, they do have similar genes and are widely used to investigate biological processes. The researchers, from Harvard Medical School, inserted into the fish a gene that glows in the presence of hydrogen peroxide. They discovered that when the tail fins of these fish were injured, a burst of hydrogen peroxide was released from the wound and into the surrounding tissue. Teams of white blood cells appeared to respond to this chemical signal, arriving at the site of the […]