BERLIN—The world of arthritis research is drawing a clearer picture of the kind of patient who might develop infections, a significant recent step forward in understanding the link between infection and rheumatoid arthritis (RA), one expert reported at the European League Against Rheumatism (EULAR) 2012 Annual European Congress of Rheumatology, held June 6–9.
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“I think what’s more interesting is not whether there’s an increased risk of infection with people with arthritis,” said Alan Silman, MD, professor and medical director at Arthritis Research UK in Chesterfield, U.K. “I think what is developing is an understanding of whether we can identify which patients we need to worry about. And, if we know which patients we need to worry about, that is going to help us interpret the information about the potential level of risk from anti-TNFs [tumor necrosis factor inhibitors] and other biologics.”
In another talk during the session, Lars Klareskog, MD, professor and chair of the department of rheumatology at the Karolinska Hospital in Stockholm, Sweden, talked about the importance of taking nuanced action to prevent comorbidities associated with RA.
Earlier research, Dr. Silman said, has suggested strongly that environmental factors play a role in the development of RA. For someone with a monozygotic twin with RA, the chance of having RA is just 15%. Declines in the incidence of RA suggest that there is an environmental factor at work in the development of RA—and that factor might very well be infection.
But what is the infectious agent? Researchers haven’t made much progress there, Dr. Silman said.
“Even today, despite 40 years of study, I don’t think we’re anywhere nearer identifying what that infectious agent might be,” he said.
With the abundance of published research, Dr. Silman offered guideposts for interpreting it all.
“It’s actually quite important when you come to this literature to have, in your own mind, some questions that you need to address as you read those publications,” he said.
Such questions include asking about the nature of the organism and the infection to determine whether it’s biologically plausible that it might be involved in RA development. Physicians should also pay attention to the attack rate, noting that most people show some signs of exposure to Epstein-Barr virus, but few people have RA.
He also cautioned against the notion of the “uniqueness” of an infecting agent.
“The likelihood that rheumatoid arthritis is going to be caused by a single infectious organism is very, very distant and, therefore, … attempting to use epidemiological methods, for example, to find the single organism that causes arthritis, is likely to come up with a blank,” Dr. Silman said.
Progress in Determining Risk
The most progress has been made in determining which patients might be at the greatest risk, with much attention given to biologics.