CHICAGO—Medicine is in the middle of an infectious-disease “revolution” that seems almost destined to lead to prevention through immunization of many diseases, including rheumatic illnesses, that never were previously thought to involve transmissible agents, an infectious disease specialist said in a session at the ACR’s 2016 State-of-the-Art Clinical Symposium.
An array of unlikely and fascinating connections between infections and diseases have been discovered over the past several decades—links of viruses and cancer, the discovery that the key to peptic ulcer disease isn’t acid, but the bacterium Helicobacter pylori, to name a couple of examples. And the rate of research in this area is mushrooming, said Bennett Lorber, MD, MACP, professor of medicine at the Lewis Katz School of Medicine at Temple University.
A Paradigm Shift
“There’s been a giant paradigm shift in our understanding of the relationship between microorganisms and human beings,” said Dr. Lorber, who himself is barely able to contain his excitement at some of the amazing findings. “We’re in the middle of a scientific revolution.”
One of the more incredible discoveries was the Nobel Prize-winning discovery that what appeared to be a neurodegenerative disease, Kuru, in people who live in the highlands of Papua New Guinea, was actually a transmissible disease with an incubation period of years or decades. The highlanders honor their dead by eating them, and the disease was being transmitted this way: Those who prepared or ate the brains of the dead had the highest rates of attack.
Spongiform encephalopathies, like Kuru, are caused by tiny bits of protein with no nucleic acid, or prions, a discovery so contrary to conventional science it was “heretical,” Dr. Lorber said. The discovery won Stanley Prusiner, MD, the Nobel Prize in 1997.
In PANDAS—pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections—children who get strep throat within two months have a dramatic onset of obsessive compulsive disorder, and those with OCD suddenly worsen. Penicillin prophylaxis helps with this, Dr. Lorber said.
The potential role of infectious agents can be seen in rheumatic diseases, as well.
People with rheumatoid arthritis have periodontal diseases more often, and worse cases of it, than controls. The major cause of periodontitis is the bacterium Porphyromonas gingivalis, which produces arginine proteinases that it needs in order to live in gingival crevices. One of these proteinases, peptidylarginine deiminase, coverts arginine to citrulline. Of course, people with RA have antibodies to cyclic citrullinated peptides.1