A small but significant number of people with Lyme disease continue to suffer from symptoms long after the end of antibiotic therapy. A study released Monday revealed that fragments of the Lyme bacteria can persist in inflamed joints of patients even after taking antibiotics.
Lyme arthritis, the most common feature of advanced disease, leaves patients with swollen and painful joints. Researchers examining synovial fluid from these inflamed joints have also discovered antibodies against the persistent molecules, called peptidoglycans, that originate from the outer shell of the Lyme bacteria, according to the study published in the Proceedings of the National Academy of Sciences.
This immune response "appears to be an important part of Lyme arthritis," said lead author of the study, Brandon Jutras, an assistant professor of biochemistry at Virginia Tech. "So, if we can prevent that answer, we suggest that it could speed up the resolution or completely eliminate the symptoms."
People develop Lyme disease when a blacklegged tick bites them and passes Borrelia burgdorferi. According to the Centers for Disease Control and Prevention, approximately 30,000 new cases of Lyme are diagnosed each year in the United States. Most cases are treated successfully with antibiotics, but if left untreated, the infection can spread to the joints, heart, and nervous system. Even in those who receive early treatment, several weeks of antibiotics do not always result in a complete resolution of symptoms.
After treatment, Lyme Disease Syndrome, a term that doctors and researchers prefer to chronic Lyme disease, has been the subject of controversy for decades. Initially, some doctors suggested that patients imagine their symptoms. But recent studies have shown significant changes in the body of patients with PTLDS. What is still unknown is whether the symptoms of PTLDS are sometimes caused by a bacterium that has not been eliminated by antibiotic treatments or by persistent changes in the immune system caused by the disease – or both.
"We have gone from knowing nothing about the disease, to not knowing if patients actually present symptoms, namely that they are really sick," said Armin Alaedini, immunologist and assistant professor of medicine at Columbia University. "The work done in my lab over the last 10 years on PTLDS shows that something is going on with the immune system. We see objective markers indicating the persistence of inflammation. "
Scientists estimate that 10 to 20% of patients diagnosed and treated for Lyme disease continue to suffer from symptoms such as arthritis, brain fog, pain, and fatigue.
Although Jutras' work is focused on Lyme arthritis, it is quite possible that the results of this study will apply to other persistent symptoms of Lyme disease.
"Whenever bacteria grow, no matter where they grow, they shed peptidoglycan. It therefore seems plausible that this may play an important role in other manifestations of advanced Lyme disease, "said Jutras.
The new findings "could constitute an important new look at Lyme arthritis and perhaps on other consequences of infection with Borrelia burgdorferi," said Mark Soloski, immunologist and professor of medicine. at the Johns Hopkins School of Medicine and co-director of basic research the Lyme Disease Research Center Johns Hopkins, who like Alaedini did not participate in the new study.
Soloski's own research reports dysfunctions of the immune system. "Our patients have had inflammation in unique regions of the brain, suggesting that an immune process could be causing the symptoms," Soloski said.
Lyme test challenges
Scientists have not yet found a way to confirm that the Lyme bacteria has been completely banned, due to some peculiarities of this nasty virus, said Soloski. It does not spend a lot of time in the blood, quickly infiltrating the tissues, and it does not grow well in a culture, allowing most bacterial infections to be confirmed.
For Kim Lewis, "the issue of persistent bacteria is still very open."
"My team is looking for better compounds to treat Lyme disease, with the concern of doing something potentially simple – finding a better drug to treat acute illness, which could prevent PTLDS," said Lewis, director of the center. of antimicrobial discovery and distinguished from the University Professor at Northeastern University, who did not participate in the new study.
The hope is also that the right compound can eradicate any persistent bacteria in people with PTLDS, said Lewis.
As for the new study, it leaves open the question of whether there are still bacteria in the joints of patients with Lyme arthritis, said Lewis. "The authors believe that the peptidoglycan remains in the synovial fluid after the disappearance of the pathogen. In my opinion, the pathogen remains in the joints and eliminates the antigen. It would be nice to know how things are.
To find physical explanations for the patient's symptoms, it is not necessary to determine whether the PTLDS is caused by a persistent bacterium or by a defective immune system, said Dr. Peter Novak, an assistant professor of neurology at Harvard Medical School and Director of the Autonomous Service. laboratory at Brigham Hospital and Women's. Novak, who also did not participate in the new study, and his colleagues found that patients were damaged to their small nerve and also had a decrease in blood flow in certain areas of the brain.
He suspects that the damage is due to changes in the immune system that have been triggered by Lyme infection and persist after the bacteria have been cleared. For patients who experience improvement when treated with long-term antibiotics, Novak thinks that many antibiotics also have an anti-inflammatory effect.
So, while others are looking for ways to detect the presence or absence of the bacteria, Novak's strategy is to try to make patients feel better by treating their symptoms.