Why Some Lyme Disease Patients Don't Respond To Treatment
Study: Scientists are coming closer to understanding exactly how variations in immune-system reactions can play a part in patients’ widely differing responses to Lyme disease.
The study, conducted by researchers from Johns Hopkins and Stanford, was published in the journal PLOS One.
“Physicians have recognized for many years that Lyme disease is not a uniform disease process and can vary in outcomes,” said Mark Soloski, Ph.D., a professor of medicine and senior author of the report. “Our experiments have linked such differences to specific immune pathways controlled by elements of the immune system…This could be a big step forward in managing this disease.”
Lyme disease is caused by the bacterium Borrelia burgdorferi, which is transmitted to humans through the bite of infected ticks. There are an estimated 300,000 new cases annually.
Symptoms can include fever, headache, fatigue and a circular, red skin rash. Arthritis, nervous system abnormalities and heart rhythm abnormalities can appear weeks or even months after infection.
Although treatment with antibiotics usually restores health within a few weeks, some patients develop post-treatment Lyme disease syndrome, whose symptoms include fatigue, pain or joint and muscle aches that can last for several months. The exact cause is not well understood, and the symptoms are difficult to treat, the researchers say.
In the latest study, the investigators measured the levels of molecules and proteins released by the liver as part of the inflammation process in Lyme disease. They looked at 44 patients with Lyme disease and 23 healthy people used as controls.
By measuring those molecules and proteins, the researchers found that patients with higher levels had more severe symptoms of the illness, meaning that their immune system didn’t have a strong response.
The researchers theorize that these variations are linked to a patient’s response to Lyme disease – i.e. whether antibiotic treatment will be effective or not, and whether the patient will develop post-treatment Lyme disease syndrome.