Immune responses to Borrelia burgdorferi in patients with reactive arthritis.

In reactive arthritis (ReA), including Reiter's syndrome, a close relationship between chronic enteric and genitourinary infections and the clinical features of enthesitis has been described. In contrast, in Lyme arthritis, a distinct clinical entity, chronic infection with the tick-transmitted spirochete Borrelia burgdorferi has been associated with the disease. In a prospective study, 51 patients with ReA were tested for evidence of chlamydial and spirochetal infection. The presence of Chlamydia was determined by culture in 8 patients, and 7 additional patients had markedly elevated antibody titers. In 9 patients, antibodies specific to B burgdorferi were found. Purified peripheral blood T lymphocytes of all 9 patients proliferated specifically to stimulation with macrophages pre-pulsed with B burgdorferi antigens. Compared with other protein antigens, higher numbers of antigen-pulsed macrophages were necessary to activate B burgdorferi-specific T cells. Although antibody titers decreased in response to antibiotic treatment in 8 of 9 patients, second-line therapy with sulfasalazine or methotrexate was required to obtain clinical remission. These data suggest that chronic infection with B burgdorferi can cause ReA. In predisposed individuals, the arthritogenic immune response might be triggered by persisting infectious agents independent of their antigenic specificities.