Australian scientists discover how liver kills "killer cells"

Australian scientists at the Centenary Institute in Sydney have discovered that the liver destroys the "killer" T-cells, which target donor organs, reducing organ rejection. Their discovery, published on Tuesday in the journal Proceedings of the National Academy of Sciences, opens the way to both new approaches to transplant rejection and to the fight against hepatitis and other chronic liver diseases which affect over 200,000 Australians and hundreds of millions of people worldwide. The scientists have seen for the first time (in mice) how the liver goes independent, engulfing and destroying the body's defense troops - T-cells. What the researchers have discovered is the liver goes around this process: liver cells signal to naive T-cells and digest them before they have a chance to become killer T-cells. "The liver is an amazing organ," said Dr. Patrick Bertolino, the leader of the research team at the Centenary Institute. "Most people think it just breaks down alcohol, but it's the factory of the body breaking down substances we don't want and making the ones that we do." Bertolino said the study helped illustrate why liver transplants were rarely rejected but other donor organs were more likely to fail. "We now know liver cells also have the ability to subvert the orders of the immune system," he said. The Australian scientists believe if they can harness the way the liver controls T-cells, there is a chance that organ transplant recipients won't need immunosuppressive drugs. Instead, patients could be given new drugs which leave their immune systems intact but stop "killer" T-cells from attacking the donor organ. The new drugs could also be used to help the liver defend itself from common infections like hepatitis C, for which there is no vaccine. However, the scientists believe it is likely to take another ten years plus before the new drugs derived from the findings enter clinical trials.