D Baeten

Systematic safety follow up in a cohort of 107 patients with spondyloarthropathy treated with infliximab: a new perspective on the role of host defence in the pathogenesis of the disease?

Background: Recent studies with infliximab indicate the therapeutic potential of tumour necrosis factor α blockade in spondyloarthropathy (SpA). Because defective host defence is implicated in the pathogenesis of SpA, the potential side effects of this treatment due to impact on the antimicrobial defence are a major concern. Objective: To report systematically the adverse events seen in a large cohort of patients with SpA treated with infliximab, with special attention to bacterial infections. Patients and methods: 107 patients with SpA were treated with infliximab for a total of 191.5 patient years. All serious and/or treatment related adverse events were reported. Results: Eight severe infections occurred, including two reactivations of tuberculosis and three retropharyngeal abscesses, and six minor infections with clear bacterial focus. One patient developed a spinocellular carcinoma of the skin. No cases of demyelinating disease or lupus-like syndrome were seen. Two patients had an infusion reaction, which, however, did not relapse during the next infusion. Finally, three patients with ankylosing spondylitis developed palmoplantar pustulosis. All patients recovered completely with adequate treatment, and infliximab treatment had to be stopped in only five patients with severe infections. Conclusions: Although the global safety of infliximab in SpA is good compared with previous reports in rheumatoid arthritis and Crohn’s disease, the occurrence of infections such as tuberculosis and retropharyngeal abscesses highlights the importance of careful screening and follow up. Focal nasopharyngeal infections and infection related symptoms, possibly induced by streptococci, occurred frequently, suggesting an impairment of specific host defence mechanisms in SpA.

Repeated infusions of infliximab, a chimeric anti-TNFα monoclonal antibody, in patients with active spondyloarthropathy: one year follow up

Background: In a pilot study, the anti-tumour necrosis factor α monoclonal antibody, infliximab, induced a rapid and significant improvement in global, peripheral, and axial disease manifestations of patients with active spondyloarthropathy. Objective: To determine whether repeated infusions of infliximab would effectively and safely maintain the observed effect. Methods: Safety and efficacy of a maintenance regimen (5 mg/kg infliximab every 14 weeks) was evaluated using the measurements reported in the pilot study. Of the 21 patients, 19 completed the one year follow up for efficacy; two patients changed to another dosing regimen after week 12 owing to partial lack of efficacy. However, they are still being followed up for safety analysis. Results: After each re-treatment a sustained significant decrease of all disease manifestations was observed. Before re-treatment, symptoms recurred in 3/19 (16%) at week 20, in 13/19 (68%) at week 34, and in 15/19 (79%) at week 48. No withdrawals due to adverse events occurred. Twelve minor infectious episodes were observed. Twelve patients (57%) developed antinuclear antibodies; in four of them (19%) anti-dsDNA antibodies were detected. However, no lupus-like symptoms occurred. Conclusion: In this open study of infliximab in patients with active spondyloarthropathy, the significant improvement of all disease manifestations was maintained over a one year follow up period without major adverse events. Although recurrence of symptoms was noted in a rising number of patients before each re-treatment, no loss of efficacy was observed after re-treatment.

Anti-citrullinated peptide antibodies may occur in patients with psoriatic arthritis

Background: Anti-cyclic citrullinated peptide (anti-CCP) antibodies are considered highly specific markers of rheumatoid arthritis. Despite the high specificity of the test, anti-CCP antibodies have also been observed in psoriatic arthritis. Objective: To determine the frequency of anti-CCP antibodies in psoriatic arthritis and to describe the clinical characteristics of such patients. Methods: Serum samples from 192 patients with psoriatic arthritis were analysed for anti-CCP antibodies. A previously defined cut off point was applied at a specificity level of ⩾98.5% (42 U/ml). Antibodies against pepA and pepB (two synthetic citrullinated peptides) were determined on samples containing anti-CCP antibodies by line immune assay. The swollen joint count and the numbers of affected joints (present or past) were recorded. Clinical features were noted and if available radiographs of hands and feet were scored for erosions. Rheumatoid factor was determined in all samples. Results: Anti-CCP antibodies were found in 15 patients (7.8%); 13 of 15 anti-CCP2 positive samples were also positive for anti-pepA or pepB antibodies. The prevalence of anti-CCP antibodies was higher than expected in view of the highly specific cut off applied in the test. Detailed analysis of the clinical and radiological features makes it improbable that the high prevalence of anti-CCP antibodies resulted solely from concomitant psoriasis and rheumatoid arthritis or from misclassification. Conclusions: Anti-CCP antibodies may be present in patients with psoriatic arthritis. Although some of the present cohort could have had psoriasis with concomitant rheumatoid arthritis, a proportion at least had the typical characteristics of psoriatic arthritis as the primary diagnosis.

Impaired Th1 cytokine production in spondyloarthropathy is restored by anti-TNFα

OBJECTIVES To evaluate the effect of anti-TNFα on the Th1 and Th2 cytokines in patients with spondyloarthropathy (SpA). METHODS Peripheral blood mononuclear cells (PBMC) were obtained from 20 patients with active SpA treated with infliximab (5 mg/kg). For comparison, PBMC were also obtained from 15 healthy controls and 19 patients with active rheumatoid arthritis (RA). After stimulation with PMA/ionomycin, the intracellular cytokines interleukin (IL)2, IL4, IL10, and interferon (IFN)γ were determined in CD3+ T cells and in CD3+/CD56+ natural killer (NK) T cells by flow cytometry. RESULTS At baseline the percentage of T cells positive for IFNγ (p=0.020) and IL2 (p=0.046) was decreased in patients with SpA compared with healthy controls, while IL10 (p=0.001) was increased. This cytokine profile, confirmed by the mean fluorescence intensities (MFI), was more pronounced in CD3+/CD8– cells and contrasted with higher IL2 production in RA. NK T cells, characterised by high IL4 and IL10 numbers, were also increased in patients with SpA (p=0.017). Treatment with infliximab induced a significant and persistent increase in IFNγ and IL2 in patients with SpA. Moreover, there was a transient decrease in IL10 and NK T cells in patients with high baseline values, resulting in values comparable with those of healthy controls. This switch in cytokine profile was seen in both the CD3+/CD8– and CD3+/CD8+ subsets. CONCLUSIONS Before treatment patients with SpA had an impaired Th1 cytokine profile compared with healthy controls and patients with RA. TNFα blockade induced restoration of the Th1 cytokines, resulting in a normal cytokine balance. These data confirm the effect of anti-TNFα on the immune changes in SpA, and provide insights into the mechanisms involved in TNFα blockade.

The effect of TNFalpha blockade on the antinuclear antibody profile in patients with chronic arthritis: biological and clinical implications

Since the first proof of efficacy of TNFalpha blockade, both the number of patients treated worldwide and the number of indications for treatment with TNFalpha blockers have grown steadily. Surprisingly, the profound immunomodulation induced by anti-TNFalpha therapy is associated with a relatively low incidence of immune-related complications such as lupus-like syndromes and demyelinating disease. This contrasts sharply with the prominent induction of autoantibodies such as antinuclear antibodies (ANA) and anti-dsDNA antibodies during TNFalpha blockade. Although this phenomenon has been recognized for several years, the clinical and biological implications are not yet fully understood. In this review, recent studies analysing the effect of TNFalpha blockade (infliximab and etanercept) on the ANA profile in autoimmune arthritis will be discussed. Taken together, these reports indicate that the prominent ANA and anti-dsDNA autoantibody response is 1) not a pure class effect of TNFalpha blockers, 2) independent of the disease background, 3) largely restricted to the induction of short-term IgM anti-dsDNA antibodies, and 4) not associated with other serological or clinically relevant signs of lupus. Nevertheless, a careful follow-up of patients treated with TNFalpha blockers remains mandatory, including monitoring for lupus-like characteristics.

Inflamed target tissue provides a specific niche for highly expanded T-cell clones in early human autoimmune disease

Objective To profile quantitatively the T-cell repertoire in multiple joints and peripheral blood of patients with recent onset (early) or established rheumatoid arthritis (RA) using a novel next-generation sequencing protocol to identify potential autoreactive clones. Methods Synovium of patients with recent onset (early) RA (<6 months) (n=6) or established RA (>18 months) (n=6) was screened for T-cell clones by sequencing over 10 000 T-cell receptors (TCR) per sample. T cells from paired blood samples were analysed for comparison. From two patients synovial T cells were obtained from multiple inflamed joints. The degree of expansion of each individual clone was based on its unique CDR3 sequence frequency within a sample. Clones with a frequency of over 0.5% were considered to be highly expanded clones (HEC). Results In early RA synovium, the T-cell repertoire was dominated by 35 HEC (median, range 2–70) accounting for 56% of the TCR sequenced. The clonal dominance in the synovium was patient specific and significantly greater than in established RA (median of 11 HEC (range 5–24) in established RA synovium accounting for 9.8% of T cells; p<0.01). 34% (range 28–40%) of the most expanded T-cell clones were shared between different joints in the same patients, compared with only 4% (range 0–8%) between synovium and blood (p=0.01). Conclusions In RA, a systemic autoimmune disease, the inflamed synovium forms a niche for specific expanded T-cell clones, especially in early disease. This suggests that, at least in RA, autoreactive T cells should be addressed specifically in the inflamed tissue, preferably in the early phase of the disease.

A comparative phenotypical analysis of rheumatoid nodules and rheumatoid synovium with special reference to adhesion molecules and activation markers

OBJECTIVES (1)To analyse the in situ expression of adhesion molecules in rheumatoid nodules. (2) To compare the endothelial expression of adhesion molecules in synovial tissue and subcutaneous nodules obtained from the same patients. (3) To compare the expression of adhesion molecules and activation markers on T cell lines from nodules and synovium. METHODS (1) Immunohistochemical analysis by APAAP technique of E selectin, CD44, ICAM-1, PECAM-1, and VCAM-1 was performed on 10 rheumatoid nodules from seven patients with rheumatoid arthritis (RA); nodules and synovium were simultaneously analysed from three patients. (2) T cell lines were generated from RA nodules (n=7) and synovium (n=7) by interleukin 2 expansion, and subsequently characterised by flow cytometry for surface expression of αEβ7, α4β7, CD44, L selectin, LFA-1a, PECAM-1, and CD30. RESULTS (1) In rheumatoid nodules, the palisading layer strongly stains for ICAM-1 and PECAM-1, but less pronounced for CD44. VCAM-1 staining was usually negative. ICAM-1 is upregulated in the vessels surrounding the central zone of fibrinoid necrosis. The immunohistological picture in different nodules derived from the same patient was similar. (2) The endothelial expression of adhesion molecules is comparable in RA nodules and synovium on an individual level, except for E selectin, which is overexpressed in nodule endothelium. (3) T cell lines from nodules and synovium display similar adhesion molecule profiles. However, the expression of CD30, a T cell activation marker linked with Th2 subsets, is higher in nodules compared with synovium. CONCLUSION These data support a recirculation hypothesis of T cells between articular and extra-articular manifestations in RA, although the activation state of the T cells in each of these localisations may differ.

History and diagnostic value of antibodies to citrullinated proteins in rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory joint disease characterized by the presence of autoantibodies. The best known autoantibody is the rheumatoid factor. Another group of antibodies directed against citrullinated epitopes is proven to be more specific for rheumatoid arthritis. This review gives an overview of the history of the different anti-citrullinated protein antibody detection methods and their diagnostic and prognostic properties in RA.

Detection of genuine anti-citrullinated protein antibodies in mice reveals their presence in BALB/c but not DBA/1 and SJL mice hyperimmunised with citrullinated collagen

Antibodies against citrullinated proteins (ACPA) occur in 60–70% of all rheumatoid arthritis (RA) patients with a specificity of 95%. The role of the immune response against citrullinated proteins in the pathophysiology of RA remains unknown, because studies in experimental models yielded contrasting results. It is unclear whether mice develop antibodies crucially dependent on citrullination of the epitope. The authors aimed to develop a reliable method to detect ACPA in mice and to assess the development of ACPA in different mouse …

FRI0150 Mtor blockade by rapamycin decreases arthritis and spondylitis development and severity in hla-b27 transgenic rats

Background HLA-B27 misfolding is thought to play an important role in the pathogenesis of spondyloarthritis (SpA), possibly through triggering of ER stress and the unfolded protein response. One of the mechanisms that regulates the unfolded protein response is autophagy. Autophagy is a process that degrades proteins, cytoplasmic particles and organelles in lysosomes and is regulated by protein kinases, mechanistic target of rapamycin (mTOR) and AMP activated protein kinase. Objectives To study whether blockade of mTOR will affect spondyloarthritis development and/or severity in the Mycobacterium tuberculosis (M. tub) induced disease HLA-B27 tg rat model. Methods 6 weeks old, female or orchiectomized male HLA-B27/Huβ2m transgenic rats were immunised with 60–90 µg heat-inactivated M. tub in IFA. Rats were prophylactically or therapeutically treated three times a week intra-peritoneally with 1.5 mg/kg rapamycin or vehicle. Clinical measurements included weight, clinical scores for spondylitis and arthritis, and hind paw swelling measured by plethysmometry. After 5 weeks of treatment rats were sacrificed; axial and peripheral joints were isolated for histology and metacarpophalangeal joints, spleen and lymph nodes were isolated for RNA isolation. Results In the prophylactic experiment 72.7% (8/11) and 18.2% (2/11) rapamycin treated rats developed arthritis and spondylitis compared to respectively 100% (13/13; p=0.0225) and 92.3% (12/13; p<0.0001) control animals. Also severity of arthritis and spondylitis was significantly decreased in rapamycin treated animals compared to control treated animals; mean arthritis severity of diseased rats was respectively 0.45 versus 7.15 on a scale from 0–12 (p<0.0001) and mean spondylitis severity was respectively 0.18 versus 2.07 on a scale from 0–3 (p<0.0001). Clinical findings were confirmed by histology with a significant decrease of inflammation (p<0.0001), bone- and cartilage destruction (p=0.0021) and new bone formation (p=0.0010) in peripheral joints of rapamycin treated rats compared to vehicle treated rats and a similar trend was observed in spinal joints. Also in a therapeutic setting rapamycin treatment decreased arthritis severity (mean score of 6 compared to 8.8 in controls; p=0.0317) and spondylitis severity (mean score of 1.23 compared to 2.8 in controls; p=0.0159). Histology for the therapeutic experiment is currently being performed as well as RNA analyses for autophagy genes and pro-inflammatory cytokines, like IL-17A and TNF. Conclusions mTOR blockade significantly suppressed arthritis and spondylitis in the M. tub induced disease HLA-B27 transgenic rat model of SpA. Disclosure of Interest S. Chen: None declared, M. van Tok: None declared, D. Pots: None declared, J. Taurog: None declared, M. van de Sande: None declared, D. Baeten Employee of: UCB Pharma, L. van Duivenvoorde: None declared