Propensity to excessive proinflammatory response in chronic Lyme borreliosis.

The clinical course of Lyme borreliosis is extremely variable. However, all the clinical manifestations, acute or chronic, are characterized by strong inflammation. Borrelia burgdorferi can induce the production of several proinflammatory and anti-inflammatory cytokines. The aim of our study was to find out whether the balance between inflammatory and regulatory mechanisms is important in determining the course of Lyme borreliosis. 13 patients with early Lyme borreliosis, 8 patients with chronic Lyme disease with neurological or joint manifestations, and 15 age- and sex-matched healthy controls were studied. Chronic forms of Lyme borreliosis were characterized by stronger TNF-alpha response by monocytes to lipopolysaccharide as well as to borrelia antigen compared to early Lyme borreliosis and the healthy state. The percentage of IL-10-secreting monocytes in response to borrelia lysate was lower in the Lyme borreliosis patients than in healthy controls. The percentage of CD4(+) CTLA-4(+) regulatory T cells showed the highest values in early Lyme borreliosis. We conclude that chronic forms of Lyme borreliosis can evolve due to an aberrant innate proinflammatory response.