Gene clue in autoimmune disease research

An international team of researchers has identified a genetic basis for systemic lupus erythematosus (SLE), a disease in which the immune system attacks its own body cells. The scientists, led by Dr Marta Alarcon-Riquelme at the University of Uppsala in Sweden, looked at the genetic make-up of more than 2500 family members affected by the illness. They found that a particular altered version of a gene called PDCD1 is present up to three times more often in patients with SLE than it is in unaffected people.

In people with SLE, or lupus as it is commonly known, the immune system starts to attack healthy cells in the joints, kidneys, lungs and other organs. Previous research suggested that PCDC1 might be involved - mice lacking the gene develop an illness similar to lupus. The new findings, published in Nature Genetics, 'give new insight to understanding the disease' conclude Dr Alarcon-Riquelme and colleagues. Commenting on the discovery, Tim Behrens, of Minnesota Medical School in the US, said 'this is a very important finding'. He added that PDCD1 is involved in controlling immune responses, so the altered version could directly contribute to the overactive immune responses seen in patients with SLE.

Robert Kimberly, of the University of Alabama, US, said that the results bolster the idea that several genes, in conjunction with environmental factors, contribute to lupus. Previous research indicates that at least five other genes might be involved, but the PDCD1 study is the first to identify a particular genetic susceptibility.