A small but significant number of people with Lyme disease continue to suffer from symptoms long after finishing an antibiotic treatment. The Lyme arthritis, the most common feature of late-onset disease, has been found to be the most common feature of late- stage disease, leaves patients with swollen, painful joints. Researchers examining synovial fluid from these inflamed joints also found antibodies to the persisting molecules, called peptidoglycans, that come from the outer covering of Lyme bacteria, according to a study published in the Proceedings of the National Academy of Sciences
. Immune response "appears to be an important part of Lyme arthritis," said Brandon Jutras, an assistant professor of biochemistry at Virginia Tech. "
People develop Lyme disease when a black-legged tick bites them and in the process transmits the bacterium Borrelia burgdorferi. Every year there are about 30,000 new cases of Lyme diagnosed in the U.S., according to the Centers for Disease Control and Prevention. Most cases are treated with antibiotics, but if left untreated, the infection can spread to the joints, heart and nervous system. Even though there are many antibiotics that do not always result in a complete resolution of symptoms
Post-treatment Lyme disease syndrome, the term doctors and researchers prefer over chronic Lyme disease, has been a subject of controversy for decades. Initially, some doctors suggested that patients were imagining their symptoms. Recent studies have found evidence of significant changes in the PTLDS patients. What is not known yet is whether PTLDS symptoms are being driven in some cases by bacteria that did not get wiped out by antibiotic treatments or by persistent immune system changes that the disease caused ̵
"We've gone from not knowing that they are really sick, "said Armin Alaedini, an immunologist and assistant professor of medicine at Columbia University. "The work in my lab over the past 10 years on PTLDS shows that something is going on with the immune system. We find objective markers indicating the persistence of the inflammation. "
Scientists estimate that 10 to 20 percent of patients diagnosed and treated for Lyme continue to suffer symptoms such as arthritis, brain fog, pain and fatigue
While Jutras's work focused on Lyme arthritis, it is quite possible that the findings may apply to other lingering Lyme symptoms
"Whenever and wherever the bacteria grow, they shed peptidoglycan, so it seems plausible that it may be important in other late-stage Lyme manifestations, "Said John Solomon, an immunologist and professor of medicine at the Johns Hopkins School of Medicine, and said," It's a good idea to have a new understanding of Lyme arthritis and possibly other outcomes of infection with Borrelia burgdorferi. " co-director for basic research for the Johns Hopkins Lyme Disease Research Center, who like Alaedini was not involved in the new study
Soloski's own research poi nts to immune system malfunctions. "Our patients have shown inflammation in unique regions of the brain, suggesting an immune process may be driving the symptoms," Soloski said.
Lyme test challenges
Scientists have not yet come up with a way to confirm that the Lyme bacteria have been completely outlawed because of certain peculiarities of this nasty bug, Soloski said. It does not spend much time in the blood, moving quickly into the tissue, and it does not grow well in a culture, which is how most bacterial infections are confirmed.
For Kim Lewis, "the question of lingering bacteria is
"My team is looking for better compounds to treat Lyme, with an eye toward doing something potentially simple – finding a better drug to treat acute disease, which could prevent PTLDS," said Lewis , director of the Antimicrobial Discovery Center and University Distinguished Professor at Northeastern University, who was not involved in the new study.
The hope is that right compound could eradicate any lingering bacteria in people with PTLDS, Lewis said
As for the new study, it leaves open the question of whether there are still bacteria in the joints of patients with Lyme arthritis, Lewis said. "The authors think that the peptidoglycan remains in the synovial fluid after the pathogen has gone. My guess is that the pathogen remains in the joints and sheds the antigen. It would be good to know how things really are. "
When it comes to finding physical explanations for patient symptoms, it is not necessary to determine whether PTLDS is caused by lingering bacteria or a malfunctioning immune system. Peter Novak, an assistant professor of neurology at Harvard Medical School, and director of the autonomous laboratory at Brigham and Women's Hospital. Novak, who also was not involved in the new study, and his colleagues have discovered that patients end up with damage to their small nerves and also diminished blood flow to certain areas of the brain.
He suspects that damage is due to changes in the immune system that was kicked off by the Lyme infection and remain after the bacteria have been obliterated. As for patients who experience improvement when treated with long courses of antibiotics, Novak believes this is because many antibiotics also have an anti-inflammatory effect
So, while others look for ways to test for the presence or absence of bacteria, Novak's strategy is to make patients feel better by treating their symptoms