Neuroimmunomodulators in neuroborreliosis and Lyme encephalopathy

Abstract

Background

Lyme encephalopathy, characterized by non-specific neurobehavioral symptoms including mild cognitive difficulties, may occur in patients with systemic Lyme disease and is often mistakenly attributed to CNS infection. Identical symptoms occur in innumerable other inflammatory states and may reflect the effect of systemic immune mediators on the CNS.

Methods

Multiplex immunoassays were used to characterize the inflammatory profile in serum and CSF from Lyme and non-Lyme patients with a range of symptoms to determine if there are specific markers of active CNS infection (neuroborreliosis), or systemic inflammatory mediators associated with neurobehavioral syndromes.

Results

CSF CXCL13 was elevated dramatically in confirmed neuroborreliosis (n=8) and to a lesser extent in possible neuroborreliosis (n=11) and other neuroinflammatory conditions (n=44). Patients with Lyme (n=63) or non-Lyme (n=8) encephalopathy had normal CSF findings, but had elevated serum levels of IL-7, TSLP, IL-17A, IL-17F, and MIP-1α/CCL3.

Conclusions

CSF CXCL13 is a sensitive and specific marker of neuroborreliosis in individuals with Borrelia-specific intrathecal antibody (ITAb) production. However, CXCL13 does not distinguish individuals strongly suspected of having neuroborreliosis, but lacking confirmatory ITAb, from those with other neuroinflammatory conditions. Patients with mild cognitive symptoms occurring during acute Lyme disease, and/or following appropriate treatment, have normal CSF but elevated serum levels of T-helper 17 markers and T-cell growth factors. These markers are also elevated in non-Lyme disease patients experiencing similar symptoms. Our results support that in the absence of CSF abnormalities, neurobehavioral symptoms are associated with systemic inflammation, not CNS infection or inflammation, and are not specific to Lyme disease.