The Psychoimmunology of Lyme/Tick-Borne Diseases and its Association with Neuropsychiatric Symptoms
Robert C. Bransfield*
Disease progression of neuropsychiatric symptoms in Lyme/tick-borne diseases can be better understood by greater attention to psychoimmunology. Although there are multiple contributors that provoke and weaken the immune system, infections and persistent infections are significant causes of pathological immune reactions. Immune mediated ef-fects are a significant contributor to the pathophysiological processes and disease progression. These immune effects in-clude persistent inflammation with cytokine effects and molecular mimicry and both of these mechanisms may be present at the same time in persistent infections. Sickness syndrome associated with interferon treatment and autoimmune limbic encephalopathies are models to understand inflammatory and molecular mimicry effects upon neuropsychiatric symp-toms. Progressive inflammatory reactions have been proposed as a model to explain disease progression in depression, psychosis, dementia, epilepsy, autism and other mental illnesses and pathophysiological changes have been associated with oxidative stress, excitotoxicity, changes in homocysteine metabolism and altered tryptophan catabolism. Lyme dis-ease has been associated with the proinflammatory cytokines IL-6, IL-8, IL-12, IL-18 and interferon-gamma, the chemokines CXCL12 and CXCL13 and increased levels proinflammatory lipoproteins. Borrelia burgdorferi surface gly-colipids and flagella antibodies appear to elicit anti-neuronal antibodies and anti-neuronal antibodies and Borrelia burgdorferi lipoproteins can disseminate from the periphery to inflame the brain. Autism spectrum disorders associated with Lyme/tick-borne diseases may be mediated by a combination of inflammatory and molecular mimicry mechanisms. Greater interaction is needed between infectious disease specialists, immunologists and psychiatrists to benefit from this awareness and to further understand these mechanisms.