Objective: To investigate whether microbial components are present in the cells of synovial fluid or peripheral blood from patients with Salmonella-triggered reactive arthritis (ReA).
Methods: Synovial fluid cells and/or peripheral blood cells from 23 patients with Salmonella-triggered ReA and from 19 control patients with newly diagnosed rheumatoid arthritis were studied using 3 different polymerase chain reaction (PCR) techniques and immunocytochemical staining. Muramic acid from the synovial fluid was studied by gas chromatography-mass spectrometry.
Results: Salmonella chromosomal DNA was not detectable in the synovial fluid cells and peripheral blood leukocytes of patients with Salmonella ReA. Initially, positive reactions were observed in the synovial fluid cells and peripheral blood leukocytes of 3 of 17 and 3 of 18 patients with ReA, respectively, but in the subsequent PCR studies, these findings were not reproducible. Salmonella-specific antigen was detectable by immunofluorescence in the synovial fluid cells and peripheral blood leukocytes of 4 of 11 and 2 of 7 patients with ReA, respectively. Muramic acid was present in 2 of 15 synovial fluid samples from patients with ReA, but the bacterial cultures from synovial fluid were negative.
Conclusion: These findings indicate the presence of bacterial degradation products, but not bacterial DNA, in the inflamed joints of patients with Salmonella-triggered ReA.