Differential synovial Th1 cell reactivity towards Escherichia coli antigens in patients with ankylosing spondylitis and rheumatoid arthritis.

OBJECTIVE: Ankylosing spondylitis (AS) is associated with clinical and subclinical mucosal inflammation, suggesting that commensal bacteria contribute to the pathogenesis of the disease. METHODS: The frequency of Th1 cells reacting towards conserved Escherichia coli (E coli) proteins and pathogenicity factors in peripheral blood mononuclear cells (PBMNC) and synovial fluid mononuclear cells (SFMNC) of patients with AS and those with rheumatoid arthritis (RA) was determined. PBMNC from healthy individuals were included as controls. RESULTS: Higher frequencies of Th1 cells reacting to conserved E coli proteins were observed in SFMNC and, to a lesser extent, in PBMNC of patients with AS compared with patients with RA (SFMNC, p<0.01; PBMNC, p<0.05). In contrast, the frequencies of cytomegalovirus- and staphylococcal enterotoxin B (SEB)-induced Th1 cells did not differ between patients with AS and those with RA in SFMNC, and SEB-induced Th1 cell frequencies in PBMNCs were even higher in patients with RA than in those with AS (p<0.05). CONCLUSIONS: The high frequency and enrichment of E coli-specific CD4 T cells in the inflamed joints of patients with AS but not those with RA suggests that commensal bacteria are relevant antigens in AS that might trigger the disease.

Impaired peripheral Th1 CD4+ T cell response to Escherichia coli proteins in patients with Crohn's disease and ankylosing spondylitis.

BACKGROUND: To clarify the impact of T cell responses towards enteric antigens for chronic intestinal inflammation, we determined T helper 1 reactivity towards conserved Escherichia coli proteins in patients with Crohn's disease (CD) and healthy individuals and patients with ankylosing spondylitis (AS), who also often show microscopic inflammatory lesions within the gut or even develop overt inflammatory bowel disease. METHODS: We determined the frequency of IFNγ+CD40L+ cells/CD4+ T cells after stimulation of whole blood with pools of E. coli proteins. RESULTS: The E. coli-specific Th1 response was significantly reduced in CD patients and to a lower extent also in AS patients. CONCLUSIONS: E. coli is a target for polyclonal Th1 responses in healthy individuals. The impairment of these responses in CD and AS patients might be due to recruitment of enterobacteria-specific Th1 cells to the gut or might reflect inadequate priming of adaptive immune response.

Synovial and peripheral blood CD4+FoxP3+ T cells in spondyloarthritis.

OBJECTIVE: Regulatory T cells are characterized by expression of the transcription factor FoxP3 and are thought to be involved in the pathogenesis of autoimmune diseases. We determined the frequency and phenotypic characteristics of CD4+FoxP3+ T cells in the blood and synovial fluid (SF) of patients with inflammatory joint diseases. METHODS: SF from 10 patients with ankylosing spondylitis (AS), 20 patients with other spondyloarthritides or with peripheral arthritis (pSpA), and 12 patients with rheumatoid arthritis (RA), and peripheral blood (PB) from 22 patients with AS, 19 with pSpA, 15 with RA, and 12 healthy controls were stained for CD4, FoxP3, CD25, and CD127 and different effector cytokines and then analyzed by flow cytometry. Methylation pattern of the Treg-specific demethylated region (TSDR) was determined after bisulfite treatment by quantitative polymerase chain reaction. RESULTS: In all groups of patients we observed higher frequencies of Foxp3+ cells/CD4+ T cells within SF compared to PB. The frequency of synovial Foxp3+ cells/CD4+ T cells was significantly higher in patients with pSpA (18.79% ± 6.41%) compared to patients with AS (9.69% ± 4.11%) and patients with RA (5.95% ± 2.21%). CD4+FoxP3+ T cells were CD25+ and CD127- and lacked effector cytokine production in any of the different patient groups. The majority of the CD4+CD25+CD127- T cells showed demethylation of the TSDR within the Foxp3 locus, confirming its regulatory phenotype. CONCLUSION: Our data show accumulation of Foxp3+ T cells within inflamed joints. These Foxp3+ T cells are mainly of stable T regulatory phenotype. The high frequency of Foxp3+ T cells in pSpA might contribute to the spontaneous resolution and remitting course of arthritis in pSpA as compared to the more persistent joint inflammation in RA.

Analysis of IL-17(+) cells in facet joints of patients with spondyloarthritis suggests that the innate immune pathway might be of greater relevance than the Th17-mediated adaptive immune response.

INTRODUCTION: In this study, we analysed the number of IL-17(+) cells in facet joints, in the peripheral blood (PB) and synovial fluid (SF) of spondyloarthritis (SpA) patients and compared these results with those of patients with other rheumatic diseases and controls. METHODS: Immunohistochemical analysis of IL-17(+) cells was performed in facet joints of 33 ankylosing spondylitis (AS) patients and compared with data from 20 osteoarthritis (OA) patients. The frequency of IL-17(+)CD4(+) T cells in PB and SF of SpA patients (PB n = 30, SF n = 11), rheumatoid arthritis (RA) patients (PB n = 14, SF n = 7), OA patients (PB n = 10) and healthy controls (PB n = 12) was analysed after stimulation with Staphylococcus aureus Enterotoxin B and phorbol 12-myristate 13-acetate/ionomycin and quantified by flow cytometry. RESULTS: In AS facet joints, the frequency of IL-17-secreting cells was significantly higher than in samples obtained from OA patients (P < 0.001), with a slight predominance of IL-17(+) cells among the mononuclear cells (61.5% ± 14.9%) compared to cells with polysegmental nuclei. Immunofluorescence microscopy revealed that the majority of IL-17(+) cells were myeloperoxidase-positive (35.84 ± 13.06/high-power field (HPF) and CD15(+) neutrophils (24.25 ± 10.36/HPF), while CD3(+) T cells (0.51 ± 0.49/HPF) and AA-1(+) mast cells (2.28 ± 1.96/HPF) were less often IL-17-positive. The frequency of IL-17(+)CD4(+) T cells in the PB and SF of SpA patients did not differ significantly compared to RA patients, OA patients or healthy controls. CONCLUSIONS: Our data suggest an important role for IL-17 in the inflammatory processes in AS. However, the innate immune pathway might be of greater relevance than the Th17-mediated adaptive immune response.

In vitro observations of T cell responsiveness to recall antigens during tumor necrosis factor-alpha-blocking therapy in patients with ankylosing spondylitis.

OBJECTIVE: Anti-tumor necrosis factor-alpha (TNF-alpha) therapy can induce reactivation of tuberculosis and an increase of other infections in patients with ankylosing spondylitis (AS). This raises the question if an alteration of T cell function can be detected by in vitro analysis to identify patients who might be more at risk of acquiring such infectious diseases. METHODS: We examined peripheral blood from AS patients without history of tuberculosis before and after 10-14 and 24-36 weeks of therapy with adalimumab (n = 8) or infliximab (n = 10). Fresh peripheral blood mononuclear cells were stimulated with cytomegalovirus antigens and with the Mycobacterium tuberculosis antigen purified protein derivative and early secretory antigen target 6. Interferon-gamma production of CD4+ T cells was assessed after in vitro antigen-specific stimulation by intracellular cytokine staining and flow cytometry. RESULTS: There was no significant change, either decrease or increase, of the T cell response to recall antigens during therapy compared to controls without treatment, if the mean values of all patients treated with adalimumab or infliximab were compared at the given timepoints. However, analysis on the individual patient level of such T cell responses revealed 1 adalimumab-treated patient and 2 infliximab-treated patients with a clear decrease of T cell response during therapy. Longterm analysis indicated that such a decrease of T cell responsiveness is generally transient and reconstituted at the latest after 52 weeks. CONCLUSION: Some patients treated with adalimumab or infliximab showed a decrease of T cell responsiveness, which seems to be transient. These patients in particular might be at risk for intracellular infections.

Alberta: new bill will allow for mandatory HIV testing in emergency situations.

A private member's bill is expected to be introduced in the spring 2004 session of the Alberta Legislative Assembly that will allow for forced testing of individuals for HIV, hepatitis, and other bloodborne diseases if their bodily fluids come into contact with emergency workers or Good Samaritans. The bill will likely have strong support from within the ranks of the governing Conservatives.