Lower prevalence of Chlamydia pneumoniae DNA compared with Chlamydia trachomatis DNA in synovial tissue of arthritis patients

Objective To assess the presence of Chlamydia pneumoniae DNA in the joints of patients with reactive arthritis (ReA) and other arthritides. Methods DNA was prepared from synovial tissue (ST) and several synovial fluid (SF) samples from 188 patients with either ReA, undifferentiated oligoarthritis, or other forms of arthritis, and from 24 normal (nonarthritis) individuals. Preparations were screened using polymerase chain reaction (PCR) assays that independently targeted the C pneumoniae 16S ribosomal RNA and major outer membrane protein genes. Results Twenty‐seven of 212 ST samples (12.7%) were PCR positive for C pneumoniae DNA; 10 SF samples from these 27 patients were similarly positive. Among the PCR‐positive patients, 3 had ReA, 2 had Reiter's syndrome, 7 had undifferentiated oligoarthritis, 4 had undifferentiated monarthritis, 6 had rheumatoid arthritis, and 5 had other forms of arthritis. No samples from normal control individuals were PCR positive. Conclusion DNA of C pneumoniae is present in synovial specimens from some arthritis patients. The prevalence of this organism in the joints was lower than that of C trachomatis, and synovial presence of the organism was not associated with any distinct clinical syndrome. Widely disseminated nucleic acids such as those of C pneumoniae might have some role in the pathogenesis of several arthritides, since the organism was not found in the ST from normal control individuals.