Chlamydia andBorrelia DNA in synovial fluid of patients with early undifferentiated oligoarthritis: Results of a prospective study

Objective.More than 50% of patients with synovitis involving 1-4 joints remain classified as having undifferentiated oligoarthritis (UOA) after 1 year of disease.The clinical presentation is often similar to that of reactive arthritis (ReA) and other spondylarthropathies or to Lyme arthritis.We therefore determined how often Chlamydia trachomatis (Ct) and Borrelia burgdorferi (Bb) can be identified in patients with UOA, by using an extensive laboratory approach.Methods.We prospectively studied 52 patients with UOA who presented at an early synovitis clinic in a region highly endemic for Lyme disease.Patients were examined by standardized clinical and immunoserologic procedures.Synovial fluid was screened for the presence of Ct and Bb DNA by polymerase chain reaction (PCR).Urine was tested for Ct DNA by ligase chain reaction, and serum was tested for Ct antibodies by enzymelinked immunosorbent assay and Bb antibodies by hemagglutination test and Western blotting.PCR results in the UOA patients were compared with the results in cohorts of patients with definite rheumatoid arthritis (RA), Lyme arthritis, and Chlamydia-induced arthritis (CIA).Results.In the synovial fluid of 9 of 52 patients with UOA (17%), we found Ct DNA, and in 6 of the 52 patients (12%), Bb DNA was found.The frequency of bacteria-specific DNA was 50% (7 of 14) in CIA patients and 69% (11 of 16) in patients with Lyme arthritis.No Bb or Ct DNA was found in the synovial fluid of the 31 RA patients.Conclusion.With optimized PCR protocols, it is possible to detect considerable levels of Bb and Ct DNA in the synovial fluid of patients with UOA.Although the presence of bacterial DNA does not unequivocally prove its etiologic significance, we suggest that at least onethird of patients with UOA may have a form of ReA that involves asymptomatic primary infection.Recent studies have shown that only 40-50% of patients presenting with early (Ͻ1 year's duration) synovitis can be given a definite rheumatologic diagnosis (1,2).Despite the use of extensive laboratory testing to search for bacterial infection, including standard microbiologic procedures, serology, urogenital smears, and stool cultures, as well as clinical parameters, Ͼ50% of patients remain classified as having undifferentiated oligoarthritis (UOA) (3).In this latter group of patients, the high rate of mono-and oligoarthritis, the frequency of HLA-B27, the predominance of synovitis in the lower limbs, and the good prognosis all characterize a condition similar to reactive arthritis (ReA) and the spondylarthropathies.Some investigators have therefore concluded that certain patients with UOA may have a "forme fruste" of ReA (4,5).Molecular biologic techniques such as polymer-Supported by BMBF grant 01VM9305, Biomed BMH4-CT-98-3605, and the Gesellschaft der Freunde der Medizinische Hochschule Hannover.