A study appearing in Proceedings of the National Academy of Sciences sheds new light on the relationship between the Epstein - Barr virus (EBV) and systemic lupus erythematosus (SLE, or lupus).
Researchers infected mice with a mouse model of lupus, which causes symptoms similar to human lupus. All of the lupus model mice go on to develop lupus, typically by one year of age. They then infected the mice with gammaherpesvirus 68, which acts similarly to the Epstein-Barr virus. To their surprise, antibodies that are typically associated with lupus did not increase, as the researchers expected, but rather decreased in female mice. In the mice infected with the virus, tissue damage in the kidneys (a site that is typically damaged in lupus) decreased by 60 per cent.
Epstein-Barr has long been associated with lupus. Most people are infected with the virus during childhood or the teen years. The virus causes infectious mononucleosis in up to 50 per cent of individuals, after which the virus enters a dormant state in the body. The virus, however, can become reactivated in certain individuals. EBV is found in higher numbers in individuals with lupus, which has led to speculation that EBV somehow predisposes susceptible individuals to developing autoimmune dysfunction, including lupus.
This research has important implications for lupus research. The researchers in the above study are now focusing on trying to determine how gammaherpesvirus 68 inhibits lupus in mice, which may pave the way towards new understanding and treatments for lupus in the future.
What is Systemic Lupus Erythematosus (SLE)?
SLE is an autoimmune disorder which causes chronic and acute inflammation throughout the body. Although the disease can be confined to the skin (discoid lupus), SLE is a systemic disease affecting internal organs. Individuals with lupus produce antibodies in their blood that attack their own tissues and organs.
Who is affected by lupus?
Women are affected approximately 8 times more often than are men. Symptoms usually start between the ages of 20 and 45. The disease is often called “the great pretender” because its symptoms often mimic those of other, more common diseases. It is not uncommon for individuals to be misdiagnosed for a long time before finally being diagnosed with lupus.
What are the symptoms of SLE?
- loss of appetite
- low-grade fever
- ulcers of the mouth
- painless Butterfly-shaped rash over the bridge of the nose and cheeks
- hair loss
- muscle aches
- sensitivity to sunlight
- inflammation affecting the heart and lungs (pleurisy, pericarditis)
- diminished circulation to fingers and toes (Reynaud’s phenomenon)
- kidney involvement
- other symptoms, depending on the organ involved
How is SLE diagnosed?
There are 11 criteria that have been developed by the American Rheumatism Association. Having 4 or more of the following symptoms strongly suggests a diagnosis of lupus. Some individuals never develop enough symptoms to meet the criteria for diagnosis, while others meet the criteria only after several years of watchful waiting:
- malar (butterfly) rash
- discoid skin rash (described as a patchy reddened skin rash with associated colour changes of the skin that may cause permanent scarring)
- mouth ulcers (may also affect the nose and throat)
- arthritis affecting at least two joints
- pleuritis or pericarditis
- kidney dysfunction (protein in the urine, casts)
- lupus cerebritis (brain irritation which may cause personality change, seizures, and other symptoms)
- blood count abnormalities (anaemia, low white blood cell count)
- abnormal immune function tests
- antinuclear antibodies present in the blood
How is SLE treated?
There is no cure for lupus. Steroids and immunosuppressants help to curb inflammation during acute flares of the disease and are sometimes used to prevent flares from occurring. Treatment is individually based on symptoms and organs affected. Adequate rest and diet during acute flares can help to shorten the severity of flares.