Tissue distribution and persistence of arthritogenic and non-arthritogenic Eubacterium cell walls.

OBJECTIVE: To study the tissue distribution and persistence of arthritogenic and non-arthritogenic Eubacterium cell walls (CWs), using arthritogenic Eubacterium aerofaciens and non-arthritogenic Eubacterium limosum. METHODS: Eubacterium aerofaciens or Eubacterium limosum CW was injected into Lewis rats intraperitoneally. Inflammatory changes in the synovium and periarticular tissues were graded histologically. On days 14, 28 and 56 after the injection, the presence of CW in the liver, spleen, mesenteric lymph nodes and synovium was studied by indirect immunofluorescence. In parallel, CW-derived muramic acid in the liver and spleen was measured by gas chromatography-mass spectrometry. In addition, serum TNF-alpha, IL-1 beta and IL-10 concentrations were determined by ELISA. RESULTS: Systemic injection of Eubacterium aerofaciens CW, but not of Eubacterium limosum CW, resulted in chronic arthritis. Both E. aerofaciens and E. limosum CWs were observed in the liver and spleen at all of the time points studied. In addition, Eubacterium limosum CW was present in non-arthritic synovium on day 14. It was not, however, detected in the synovium or lymph nodes on days 28 and 56, in clear contrast to the rats injected with E. aerofaciens CW. According to the analysis by gas chromatography-mass spectrometry, non-arthritogenic E. limosum CW had accumulated in the liver cells on days 14 and 28 after the injection to a greater extent than arthritogenic E. aerofaciens CW, leading to a lesser distribution in the other organs. A weak trend was observed suggesting that the production of TNF-alpha and IL-1 beta, but not of IL-10, is stimulated better by arthritogenic CW than by non-arthritogenic CW. CONCLUSION: Our results indicate that non-arthritogenic CWs are handled by the rat's defence mechanisms in a different way than arthritogenic CWs. The tissue distribution and persistence of CWs play a role in arthritogenicity, but additional factors must exist to determine why the CWs of certain bacteria are arthritogenic and those of others are not.

Salmonella-triggered reactive arthritis: use of polymerase chain reaction, immunocytochemical staining, and gas chromatography-mass spectrometry in the detection of bacterial components from synovial fluid.

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.

Antibodies to streptococcal cell wall in psoriatic arthritis and cutaneous psoriasis.

OBJECTIVE: To evaluate the possible role of streptococcal cell wall antigens in the development of psoriatic arthritis. METHODS: IgM, IgA and IgG class serum antibodies against peptidoglycan-polysaccharide (PG-PS) and peptidoglycan (PG), both from group A streptococcus, were measured in patients with psoriatic arthritis (PA), non-arthritic psoriasis (NAP), rheumatoid arthritis (RA) and in healthy controls, using ELISA. RESULTS: Both groups of psoriatic patients had elevated IgA levels specific to streptococcal PG-PS. No association with the severity of the skin disease or with the different subsets of PA was detected. Higher concentrations of IgG against the two streptococcal preparations was observed in PA than in RA. Analysis of antibody levels in patients with recent onset arthritis showed lower concentrations of IgM antibodies against streptococcal as well as control antigens in early than in late PA, whereas an overall increase of specific IgA and IgG antibodies was observed in early RA. CONCLUSION: The results suggest chronic mucosal stimulation of lymphocytes by long-lived streptococcal antigens in patients with psoriasis, without any difference observed between PA and NAP. The differences between recent onset versus established PA and RA could reflect a distinct immunopathology in the two arthritides.