Gene variant may up lupus risk

October 28, 2002

Last Updated: 2002-10-28 16:18:25 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Scientists have identified a gene variation that

may increase the risk of the autoimmune disease lupus.

In people with lupus, or systemic lupus erythematosus (SLE) as it is

officially known, the immune system loses the ability to differentiate

between its own cells and outside invaders, so it attacks healthy cells

including tissue in the joints, kidneys, lungs and other organs.

Immune-suppressing drugs are used to treat the condition, but there is no

cure. About one out of every 2,000 people in the West has lupus, which

mainly strikes women.

Previous research has zeroed in on chromosome regions that seem to be

related to lupus, but scientists have not found particular genes that

increase the risk of the autoimmune disease. A gene called PDCD1, which

contains the instructions for making an immune protein, has been under

suspicion because mice that do not have the gene develop an illness similar

to lupus.

Now a team led by Dr. Marta E. Alarcon-Riquelme, of the University of

Uppsala in Sweden, has sequenced the PDCD1 gene in more than 2,500 people

including people with lupus as well as in individuals without the disease.

They identified a variant form of the PDCD1 gene that seems to increase the

risk of lupus. The researchers report their findings in the advance online

publication of the December issue of Nature Genetics.

In a European sample, the gene variation was present in 12% of lupus

patients compared with 5% of healthy individuals. Similarly, in a sample of

Mexicans, 7% of people with lupus had the variant form of PDCD1 compared

with 2% of healthy people.

Since PDCD1 has some influence over the immune system's ability to recognize

the body's own tissue, the variation in the expression of PDCD1 may play a

role in the exaggerated immune response in lupus, according to the report.

The findings " give new insight to understanding the disease, "

Alarcon-Riquelme and her colleagues conclude.

Alarcon-Riquelme and another co-author are shareholders in Everygene AB, a

Swedish company that has filed for a patent related to the research.

SOURCE: Nature Genetics 2002;10.1038/ng1020.

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