By Leroy Leo
(Reuters) – Neurologic complications of Lyme disease such as hand and feet numbness and pain that do not resolve with treatment may be due to an exaggerated immune response rather than the infection itself, a study published on Wednesday suggests.
Researchers found that Lyme disease patients with persistent central nervous system problems have high blood levels of interferon alpha, an inflammatory protein produced by the immune system in response to infection.
These central nervous system symptoms that can also include weakness, facial muscle paralysis, vision problems, fever, stiff neck, and severe headache are known as Lyme neuroborreliosis.
If the findings are confirmed in larger studies, immunity-suppressing medicines might be used to treat patients with persistent disabling neurologic after-effects of the disease, said senior researcher Dr. Klemen Strle of Tufts University School of Medicine.
Each year, nearly 500,000 Americans are diagnosed with Lyme disease, with another 200,000 cases believed to occur in western Europe, researchers said. It is caused by a bacteria carried and spread by ticks prevalent in the U.S. upper Midwest and the northeastern and mid-Atlantic states, as well as in Europe and some parts of Canada, especially in wooded areas.
Lyme neuroborreliosis occurs in up to 15% of those who contract the illness, according to the U.S. Centers for Disease Control and Prevention (CDC), and most patients recover after treatment with antibiotics. However, around 10%-20% of patients continue to show symptoms even after treatment.
Earlier research found that Lyme-causing bacteria do not survive antibiotic treatment and therefore cannot be preventing recovery, according to the report in Emerging Infectious Diseases, a CDC publication.
For the current study, researchers in Slovenia took serial blood samples over the course of a year in 79 patients who had experienced Lyme neuroborreliosis during their acute infection, including 27 with new or lasting complications six months or more after treatment.
Patients whose symptoms had resolved by the start of the study had the lowest interferon levels. Those with the most severe and most persistent problems had the highest interferon levels, suggesting that the immune system never stopped responding leading to “low-grade, systemic inflammation,” the researchers said.
Other illnesses with prolonged symptoms believed or known to be triggered by immune system over-reaction include COVID-19, influenza and mononucleosis, the researchers said.
(Reporting by Leroy Leo in Bengaluru; Editing by Nancy Lapid and Bill Berkrot)
