Lyme disease is a serious illness caused by the Borrelia burgdorferi bacterium; now researchers have learned more about how it sticks around in the body, fighting early immune responses. Led by Dr. Utpal Pal, a Professor of Veterinary Medicine at the University of Maryland (UMD), scientists identified a protein made by the microbe that can disable an early immune response in the body. The work demonstrated that even with a perfectly functioning immune system, and even when that protein is disabled, the bacterium can still reemerge in the body. These findings, which could have major implications for the treatment of Lyme disease, have been reported in the Proceedings of the National Academy of Sciences (PNAS).
"Most people don't realize that they actually are walking around with more bacterial cells in their bodies than their own cells, so we are really bags of bacteria," explains Pal. "Most are good, but the second your body detects something that is a pathogen and can cause disease, your immune system starts to work."
The immune system will attack invaders it has detected within a few hours or days. If that isn’t enough to get rid of the problem, a large second wave of reinforcements will mount another attack. Lyme disease disrupts this system.
"Lyme disease is actually caused by your immune system," explained Pal. "This bacteria wins the first battle, and your body overreacts so much that it causes intense inflammation in all the joints and areas that the bacteria spread by sending so many reinforcements to kill it. Borrelia is then killed, but the inflammation remains and causes many of your symptoms for Lyme disease. That is why killing Borrelia in the first wave of immunity is so important."
Lyme disease is becoming more widespread and is an increasing threat to public health. The Centers for Disease Control and Prevention (CDC) has estimated that 300,000 cases of Lyme disease occur in the United States every year. It is thought that most cases go unreported, however, and that mosquito-borne diseases attract more attention.
"The majority of all vector-borne diseases in the US are actually tick-borne, and 6 of the 15 distinct tick diseases are transmitted by the Ixodes tick we study in our lab," said Pal. "The symptoms of these diseases present similarly to many other illnesses and are hard to pin down, so they are vastly underreported and an even bigger public health concern locally and globally than people realize."
Chronic Lyme disease is another problem for people who have been infected by the bacterium. Six months to a year after typical antibiotic treatments for Lyme, many patients experience recurrent symptoms of varying intensity, called Post-Treatment Lyme Disease Syndrome.
"This means there is a second line of defense for Borrelia just like for our body's immune system. This had never been observed before and gives us insight into what could be causing these chronic Lyme disease cases," said Pal.
Pal is considered an expert in this field and plans to continue his pioneering work. "I am fascinated by Borrelia, and this discovery will open the door for much more work to treat and control important diseases like Lyme disease," said Pal.
Sources: AAAS/Eurekalert! Via UMD, PNAS