Objective: To compare the pattern of antibody responses to Borrelia burgdorferi in patients with antibiotic-refractory, antibiotic-responsive, or non-antibiotic-treated Lyme arthritis as an indirect measure of spirochetal persistence or eradication.
Methods: At least 3 serial serum samples from 41 patients with antibiotic-refractory arthritis and 23 patients with antibiotic-responsive arthritis, and samples from 10 non-antibiotic-treated, historical control patients were tested for IgG reactivity with B burgdorferi sonicate and 4 differentially expressed outer surface lipoproteins of the spirochete, by enzyme-linked immunosorbent assay.
Results: Among non-antibiotic-treated patients, antibody titers to B burgdorferi antigens remained high throughout a 2-5-year period of arthritis. In contrast, in patients with antibiotic-responsive arthritis, in whom joint swelling usually resolved during a 1-month course of oral antibiotic therapy, the median antibody titers to most of the spirochetal antigens remained steady or decreased during the first 1-3 months after starting antibiotic therapy. In patients with antibiotic-refractory arthritis, who had persistent joint swelling for a median duration of 10 months despite 2-3 months of oral or intravenous antibiotics, the median titers to most antigens increased slightly during the first 1-3 months. However, by 4-6 months after starting antibiotic therapy, reactivity with all antigens declined similarly in both antibiotic-treated groups.
Conclusion: Whereas the antibody titers to B burgdorferi remained high in non-antibiotic-treated patients, the titers declined similarly 4-6 months after starting therapy in patients with antibiotic-responsive or antibiotic-refractory arthritis, suggesting that synovial inflammation persisted in patients with antibiotic-refractory arthritis after the period of infection.