Results of the study, published in Journal of Neuroinflammation, suggest new avenues for treating the long-term fatigue, pain, sleep disruption and "brain fog" associated with PTLDS, the researchers say. "There's been literature suggesting that patients with PTLDS have some chronic inflammation somewhere, but until now we weren't able to safely probe the brain itself to verify it," says Jennifer Coughlin, M.D., associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, and one of the first authors of the study report. Lyme disease is a bacterial infection transmitted to humans through tick bites. An estimated 300,000 people in the U.S. are diagnosed with Lyme disease each year, and their infections can be successfully treated with antibiotics. Doctors diagnose PTLDS if treated patients report fatigue and brain fog for at least six months after treatment. Little is known about what causes PTLDS or how to treat it, and while studies have shown that people with PTLDS have elevated markers of inflammation -- such as the chemokine CCL19 -- in their bloodstreams, it has not been clear where that inflammation may be occurring. Over the last decade, Coughlin and her colleagues optimized a positron emission tomography (PET) imaging technique in which specially labeled molecules -- or radiotracers -- bind to a protein called translocator protein (TSPO). In the brain, TSPO is released primarily by two types of brain immune cells -- microglia and astrocytes -- so levels of TSPO are higher when brain inflammation is present. - www.sciencedaily.com