What problem was studied?
Epstein-Barr virus is one of the most common viruses that infect humans, generally resulting in a very mild and brief illness in children. When EBV affects adolescents or young adults, it can result in infectious mononucleosis, a condition that results in fever, sore throat, swollen lymph glands and severe fatigue. Although symptoms usually stop within a few months, EBV remains dormant or latent in the body for the rest of the infected person's life and can become reactivated. EBV infection is more common in people with systemic lupus erythematosus (SLE or lupus) but it is not clear whether this is a cause or effect of a faulty immune system in these individuals.
In addition, people with lupus often take drugs that suppress the immune system, making them more susceptible to infections and cancer. To help prevent these complications, research is needed to better understand how the immune system in people with lupus defends against foreign invaders.
Arthritis Foundation-funded researchers involved in the study: Insoo Kang, MD, supported by an Arthritis Investigator Award; Timothy Quan, MD, supported by an AF/American College of Rheumatology Physician Scientist Development Award; and Joseph E. Craft, MD, supported by a Biomedical Science Grant and a Southern New England Chapter grant, Yale University, New Haven, CT
What was done in the study?
The research team collected blood samples from people with lupus and from healthy individuals to look at signs of EBV infection (called "viral loads"). They also examined how the immune system in both groups handled EBV infection by studying subsets of immune cells, called "T cells," which normally play a key role in defending the body against viral infections.
What were the study results?
The researchers found that the patients with lupus had a 40-fold increase in signs of EBV infection compared to the healthy subjects. The people with lupus had a higher frequency of one type of T cell (CD4) but a lower frequency of another type of T cell (CD8). The team concluded that people with lupus have a defect in their ability to control latent EBV infection that probably results from altered T cell responses to the virus.
What's the relevance to people with lupus?
This study is important because it begins to provide insights about how people with an abnormal immune system, such as in lupus, respond to infection. Adds Dr. Kang, "This is clinically important research since patients with autoimmune diseases like lupus are frequently treated with strong immunosuppressive drugs that may suppress immune responses against infection. In this study, we have shown that patients with SLE have defective control of latent EBV infection.
However, the clinical significance of such a defect is still elusive and should be determined with future studies."
Source: Journal of Immunology, January 2004 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14707107&dopt=Abstract
Research Update is compiled by Michele Boutaugh, BSN, MPH, Medical and Scientific Affairs Department, National Office.
Source: The Arthritis Foundation (online at www.arthritis.org).