Link between viral infection and autoimmune disease

Australian scientists have discovered that common viral infections can pave the way to autoimmune disease. Their work was published in the journal Immunity.

The research focused on chronic cytomegalovirus (CMV) - a member of the herpes family and a common viral infection that causes mild flu-like symptoms in healthy people but can lead to more serious illness in those with compromised immune systems. Between 50 and 80% of people in developed countries are infected with CMV.

Although normally innocuous, given the right genetic background, chronic viral infection with CMV can trigger autoimmunity - specifically, the development of Sjogren’s syndrome (SS). Professor Mariapia Degli-Esposti, from The University of Western Australia and the Lions Eye Institute, explained that SS “affects the function of salivary and lacrimal glands and leads to a debilitating disease characterised by the loss of saliva and tear production”.

SS is the second most common autoimmune disease in humans and is overwhelmingly suffered by women, with most symptoms emerging in the 40- to 60-year age group. There are two forms of the disease: primary Sjogren’s syndrome - defined as a dry eye and mouth that occurs by itself, and secondary Sjogren’s syndrome - with the same symptoms occurring in those with a major underlying disease such as rheumatoid arthritis or systemic lupus.

Professor Degli-Esposti said the researchers were “able to dissect the exact cellular and molecular mechanisms that lead to the development of this common autoimmune disease”. Their work identified a cause of SS and, in doing so, demonstrated a novel, unknown function of an immune cell population.

Professor Degli-Esposti said the researchers now know more about the pathways that lead to the disease, as well as which ones need to be targeted to improve treatment.

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