Doctor says you are cured, but you still feel the pain. Borrelia DNA persistence in Lyme disease

What Makes It Tick: Exploring the Mechanisms of Post-treatment Lyme Disease Syndrome

Post-treatment Lyme disease syndrome (PTLDS), which may also be referred to incorrectly as "chronic Lyme disease," is defined by the Infectious Diseases Society of America (IDSA) as the presence of fatigue, pain, and/or cognitive complaints with the functional impact that persists for more than six months after completing treatment for Lyme disease (LD). These symptoms occur in 10%-20% of patients previously diagnosed with LD caused by the bacteria Borrelia burgdorferi and appropriately treated with a course of antibiotics. The symptoms of PTLDS can be easily overlooked or misdiagnosed as a psychiatric manifestation in geographic locations that rarely see LD. In contrast, geographic locations with a higher prevalence of LD may be more aware of PTLDS symptoms and have higher clinical suspicion leading to this diagnosis. The pathophysiology behind the persistent symptoms some people experience from a primary infection is still largely unknown. Some mechanisms that have been proposed include permanent tissue damage and inflammation, immune system dysfunction, autoimmune response, co-infection, and even persistent infection refractory to treatment. We propose that ongoing PTLDS symptoms seem to be related to an autoimmune response to the tissue damage and inflammation caused by the viable or nonviable spirochete pathogen. At this point, PTLDS is diagnosed clinically as no quantifiable methods are available from laboratory or tissue diagnostics as of 2024. Similar pathophysiological features of PTLDS are seen in diseases such as COVID-19 or chronic fatigue syndrome (CFS). More effective diagnostic approaches might include further studies looking at a possible connection in the genomes of individuals developing PTLDS, quantifiable biomarkers, common inflammatory markers/pathways, and careful histopathological studies of human tissues.

IL-26 mediated human cell activation and antimicrobial activity against Borrelia burgdorferi

Lyme disease is an inflammatory disease caused by infection with Borrelia burgdorferi (Bb). Inflammatory sequelae of Bb infection appear to be refractory to antibiotics. An antimicrobial peptide with the ability to bind the DNA in the tissue could serve as a viable option of treatment for chronic complications of Lyme borreliosis. DNA of Bb can remain in tissues causing a prolonged inflammatory response that lead to chronic joint pain. Here we examined the effect of IL-26, a newly reported antimicrobial protein, against Bb DNA. An antimicrobial effect of IL-26 on the spirochete was observed. In human macrophages, IL-26 treated cells showed an increase in IRF activation upon Bb stimulation. Moreover, IL-26 treated macrophages showed an increased in phagocytic activity compared to untreated cells. Although no Bb DNA degradation was observed using a TUNEL assay run in an agarose gel, a Comet assay on whole bacteria showed cellular and Bb DNA degradation by IL-26. Our results showed that IL-26 (monomer and dimer) has not only the potential to control Bb growth in vitro, but it also enhances the anti-borrelial response of human macrophages. Further research aiming to characterize the role of IL-26 in controlling other aspects of the inflammatory response that could provide insight of its potential therapeutic applications are needed.