Researchers Discover Virus-Like Elements in the Human Genome Linked to the Development of Lupus, Sjogren's Syndrome

A new study from Hospital for Special Surgery revealed a virus-like element within the human genome that can potentially trigger the development of autoimmune diseases, especially lupus and Sjogren's syndrome.

Autoimmune disease is a disorder in the immune system that occurs when immune responses, which is suppose to protect the body and fight off invaders, attacks and destroys healthy organs.

The study, published in the journal Arthritis and Rheumatology, suggests that an abnormal expression of a genetic elements known as LINE-1 (L1) retroelements have the ability to set off an innate immune response similar to viral infection and may play a part in the overproduction of interferons, resulting an autoimmune disorder.

At present, the exact cause of autoimmune disease remains unknown. However, researchers believe that autoimmune disease comes from combination of genetic and environmental factors.

"We hypothesized that virus-like DNA sequences inherent in our own genomes or the RNA transcripts they produce might be driving the production of interferon and contributing to disease," said Mary K. Crow, MD, physician-in-chief at Hospital for Special Surgery and senior study author, in a statement.

To test out their hypothesis, researchers led by Dr. Crow analyzed kidney biopsy samples from 24 patients with lupus nephritis and salivary gland tissue from 31 patients with Sjogren's syndrome and compared them to healthy tissue.

The researchers noticed that the levels of L1 retroelements were increased in the patients with lupus and Sjogren's syndrome. Increase levels of L1 retroelements can cause the overproduction of interferons. Interferons are molecules that were produced by the body in the presence of viruses and other pathogens top mobilize an immune response.

"Our findings support the hypothesis that L1 retroelements, perhaps along with other virus-derived genomic elements, may contribute to the development of autoimmune disorders characterized by high levels of type 1 interferon," commented Dr. Crow in a press release.

Researchers noted that interferons play a crucial role in the complex immune response of the body to combat danger. However, elevated levels of interferons could lead to the development of autoimmune disease.