Tumor necrosis factor-alpha blockade in ankylosing spondylitis: a potent but expensive anti-inflammatory treatment or true disease modification?

Blocking tumor necrosis factor-α either with monoclonal antibodies or with soluble receptor constructs has been proven to be effective with an acceptable safety profile in patients with rheumatoid arthritis, and more recently also in the diseases belonging to the spondyloarthropathy concept. Nevertheless multiple questions still remain unresolved especially concerning longer-term treatment. Data from a recent manuscript by Baraliakos and colleagues seem to indicate that at least for the vast majority of ankylosing spondylitis patients treatment with infliximab can not be withdrawn, if one wants to control disease activity in a continuous way. Although still unproven, this might be of crucial importance with regard to structure modification and prevention of ankylosis in this chronic inflammatory disorder.

Involvement of neurotrophins and their receptors in spondyloarthritis synovitis: relation to inflammation and response to treatment

OBJECTIVE

To investigate whether expression of the four members of the neurotrophin (NT) family and their four corresponding receptors is related to synovial inflammation in patients with spondyloarthritis (SpA).

MATERIAL AND METHODS

Synovial fluid (SF) and serum NTs and their receptors were measured by ELISA. Immunohistochemistry was used for synovial tissue biopsy specimens from patients with SpA, rheumatoid arthritis, and osteoarthritis (OA). In SpA synovium, immunoreactivity of the receptors trkA and NGFRp75 was also assessed before and after 12 weeks of treatment with the monoclonal anti-tumour necrosis factor alpha antibody, infliximab.

RESULTS

mRNA transcripts of all NTs and receptors were expressed in the inflamed synovium. At the protein level, brain derived neurotrophic factor and NT-3 were significantly higher in the SF of patients with SpA than in those with OA. In contrast, ELISA of serum samples showed that the highest member in SpA was NT-4. Immunohistochemistry demonstrated that the NT receptors trkA and NGFRp75 were highly expressed in the inflamed synovium of patients with SpA, correlating with vascularity and lymphoid aggregates, respectively. Additionally, immunoreactivity of both receptors was significantly decreased after infliximab treatment.

CONCLUSIONS

NTs and their receptors are expressed in inflamed peripheral joints of patients with SpA. Their expression is not constitutive but related to inflammation and they may be involved in the local disease processes.

Transplantation of viable meniscal allograft. Survivorship analysis and clinical outcome of one hundred cases

BACKGROUND

Few medium-term or long-term reports on meniscal allograft transplantations are available. In this study, we present the results of a survival analysis of the clinical outcomes of our first 100 procedures involving transplantation of viable medial and lateral meniscal allografts performed in ninety-six patients.

METHODS

Thirty-nine medial and sixty-one lateral meniscal allografts were evaluated after a mean of 7.2 years. Survival analysis was based on specific clinical end points, with failure of the allograft defined as moderate occasional or persistent pain or as poor function. An additional survival analysis was performed to assess the results of the sixty-nine procedures that involved isolated use of a viable allograft (twenty of the thirty-nine medial allograft procedures and forty-nine of the sixty-one lateral allograft procedures) and of the thirteen viable medial meniscal allografts that were implanted in combination with a high tibial osteotomy in patients with initial varus malalignment of the lower limb.

RESULTS

Overall, eleven (28%) of the thirty-nine medial allografts and ten (16%) of the sixty-one lateral allografts failed. The mean cumulative survival time (11.6 years) was identical for the medial and lateral allografts. The cumulative survival rates for the medial and lateral allografts at ten years were 74.2% and 69.8%, respectively. The mean cumulative survival time and the cumulative survival rate for the medial allografts used in combination with a high tibial osteotomy were 13.0 years and 83.3% at ten years, respectively.

CONCLUSIONS

Transplantation of a viable meniscal allograft can significantly relieve pain and improve function of the knee joint. Survival analysis showed that this beneficial effect remained in approximately 70% of the patients at ten years. This study identified the need for a prospective study comparing patients with similar symptoms and clinical findings treated with and without a meniscal allograft and followed for a longer period with use of clinical evaluation as well as more objective documentation tools regarding the actual fate of the allograft itself and the articular cartilage.

Functional haplotypes of PADI4: relevance for rheumatoid arthritis specific synovial intracellular citrullinated proteins and anticitrullinated protein antibodies

BACKGROUND

Haplotypes of PADI4, encoding for a citrullinating enzyme, were associated with rheumatoid arthritis in a Japanese population. It was suggested they were related to the presence of anticitrullinated protein antibodies (ACPA).

OBJECTIVE

To explore the relation between PADI4 haplotypes, the presence of rheumatoid arthritis specific intracellular citrullinated proteins in synovial membrane, and serum ACPA titres.

METHODS

Synovial biopsies and peripheral blood samples were obtained in 59 patients with rheumatoid arthritis. Synovial intracellular citrullinated proteins were detected by immunohistochemistry. Serum ACPA titres were measured by anti-CCP2 ELISA. PADI4 haplotypes were determined by direct sequencing of the four exonic PADI4 single nucleotide polymorphisms.

RESULTS

PADI4 haplotype frequencies and the presence of synovial intracellular citrullinated proteins and ACPA were comparable with previous studies. There was no significant association between PADI4 haplotype 1 or 2 and the presence of synovial intracellular citrullinated proteins, although these proteins were associated with higher serum ACPA. There was no correlation between PADI4 haplotypes and serum ACPA, either by continuous analysis using the titres or by dichotomous analysis using the diagnostic cut off. Further analyses in homozygotes for haplotype 1 or 2 or in heterozygotes (1/2) also failed to show an association between PADI4 polymorphisms and ACPA. This contrasted with the clear association between ACPA levels and HLA-DR shared epitope.

CONCLUSIONS

The link between synovial intracellular citrullinated proteins and ACPA emphasises the role of deimination of synovial proteins in rheumatoid arthritis, but the biological relevance of the PADI4 haplotypes for this autoimmune process is questionable, at least in a European population.

Synovial histopathology of psoriatic arthritis, both oligo- and polyarticular, resembles spondyloarthropathy more than it does rheumatoid arthritis

At present only few biological data are available to indicate whether psoriatic arthritis (PsA) is part of the spondyloarthropathy (SpA) concept, whether it is a separate disease entity or a heterogeneous disease group with oligoarticular/axial forms belonging to SpA and polyarticular forms resembling rheumatoid arthritis (RA). To address this issue with regard to peripheral synovitis, we compared the synovial characteristics of PsA with those of ankylosing spondylitis (AS)/undifferentiated SpA (USpA) and RA, and compared the synovium of oligoarticular versus polyarticular PsA. Synovial biopsies were obtained from patients with RA, nonpsoriatic SpA (AS + USpA), and oligoarticular and polyarticular PsA. The histological analysis included examination(s) of the lining layer thickness, vascularity, cellular infiltration, lymphoid aggregates, plasma cells and neutrophils. Also, we performed immunohistochemical assessments of CD3, CD4, CD8, CD20, CD38, CD138, CD68, CD163, CD83, CD1a, CD146, alphaVbeta3, E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, S100A12, intracellular citrullinated proteins and major histocompatibility complex (MHC)-human cartilage (HC) gp39 peptide complexes. Comparing SpA (PsA + AS + USpA) with RA, vascularity, and neutrophil and CD163+ macrophage counts were greater in SpA (P < 0.05), whereas lining layer thickness and the number of CD83+ dendritic cells were greater in RA (P < 0.05). In RA, 44% of samples exhibited positive staining for intracellular citrullinated proteins and 46% for MHC-HC gp39 peptide complexes, whereas no staining for these markers was observed in SpA samples. We excluded influences of disease-modifying antirheumatic drug and/or corticosteroid treatment by conducting systematic analyses of treated and untreated subgroups. Focusing on PsA, no significant differences were observed between PsA and nonpsoriatic SpA. In contrast, vascularity (P < 0.001) and neutrophils were increased in PsA as compared with RA (P = 0.010), whereas staining for intracellular citrullinated proteins and MHC-HC gp39 peptide complexes was exclusively observed in RA (both P = 0.001), indicating that the same discriminating features are found in PsA and other SpA subtypes compared with RA. Exploring synovial histopathology between oligoarticular and polyarticular PsA, no significant differences were noted. Moreover, intracellular citrullinated proteins and MHC-HC gp39 peptide complexes, which are specific markers for RA, were observed in neither oligoarticular nor polyarticular PsA. Taken together, these data indicate that the synovial histopathology of PsA, either oligoarticular or polyarticular, resembles that of other SpA subtypes, whereas both groups can be differentiated from RA on the basis of these same synovial features, suggesting that peripheral synovitis in PsA belongs to the SpA concept.

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 > or =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.

A dose adjustment in patients with rheumatoid arthritis not optimally responding to a standard dose of infliximab of 3 mg/kg every 8 weeks can be effective: a Belgian prospective study

OBJECTIVES

To analyse the effect of a dose increase in patients with severe rheumatoid arthritis (RA) with insufficient clinical response to 3 mg/kg infliximab every 8 weeks.

METHODS

Patients suffering from active refractory RA despite methotrexate, were treated with i.v. infusions of infliximab (3 mg/kg) on week 0, 2, 6 and every 8 weeks thereafter. Based on the clinical judgement at week 22, patients received a dose increase of 100 mg from week 30 on. The American College of Rheumatology (ACR) core set for disease activity measures was regularly assessed.

RESULTS

Five hundred and eleven RA patients were included. At week 22, 61.4, 34 and 14.1% of all patients met ACR 20, ACR 50 and ACR 70 criteria, respectively, and 6.1% of patients were in remission. A low swollen joint count at baseline was correlated with improvement at week 22 for ACR 20 (P < 0.06), ACR 50 (P < 0.06) and ACR 70 (P < 0.005). The change in HAQ score between weeks 0 and 22 was predictive for response at week 54 (P < 0.01). The dose of infliximab was increased by 100 mg in 22% of the patients. Most baseline values of patients requiring dose increase were higher (P < or = 0.001) than the baseline values of the remaining patients. Increasing the dose of infliximab by one vial from week 30 on could circumvent the partial loss of response in these patients.

CONCLUSION

Infliximab use in this large out-patient cohort resulted in a significant clinical improvement. A subgroup that partially lost response during the first 22 weeks could regain response by adding 100 mg of infliximab to the subsequent doses. Due to the current study design, however, a regression to the mean like effect could not be ruled out.

Infiltration of the synovial membrane with macrophage subsets and polymorphonuclear cells reflects global disease activity in spondyloarthropathy

Considering the relation between synovial inflammation and global disease activity in rheumatoid arthritis (RA) and the distinct but heterogeneous histology of spondyloarthropathy (SpA) synovitis, the present study analyzed whether histopathological features of synovium reflect specific phenotypes and/or global disease activity in SpA. Synovial biopsies obtained from 99 SpA and 86 RA patients with active knee synovitis were analyzed for 15 histological and immunohistochemical markers. Correlations with swollen joint count, serum C-reactive protein concentrations, and erythrocyte sedimentation rate were analyzed using classical and multiparameter statistics. SpA synovitis was characterized by higher vascularity and infiltration with CD163⁺ macrophages and polymorphonuclear leukocytes (PMNs) and by lower values for lining-layer hyperplasia, lymphoid aggregates, CD1a⁺ cells, intracellular citrullinated proteins, and MHC–HC gp39 complexes than RA synovitis. Unsupervised clustering of the SpA samples based on synovial features identified two separate clusters that both contained different SpA subtypes but were significantly differentiated by concentration of C-reactive protein and erythrocyte sedimentation rate. Global disease activity in SpA correlated significantly with lining-layer hyperplasia as well as with inflammatory infiltration with macrophages, especially the CD163⁺ subset, and with PMNs. Accordingly, supervised clustering using these synovial parameters identified a cluster of 20 SpA patients with significantly higher disease activity, and this finding was confirmed in an independent SpA cohort. However, multiparameter models based on synovial histopathology were relatively poor predictors of disease activity in individual patients. In conclusion, these data indicate that inflammatory infiltration of the synovium with CD163⁺ macrophages and PMNs as well as lining-layer hyperplasia reflect global disease activity in SpA, independently of the SpA subtype. These data support a prominent role for innate immune cells in SpA synovitis and warrant further evaluation of synovial histopathology as a surrogate marker in early-phase therapeutic trials in SpA.

Serum levels of matrix metalloproteinase 3 and macrophage colony-stimulating factor 1 correlate with disease activity in ankylosing spondylitis

OBJECTIVE

To assess the usefulness of measuring serum matrix metalloproteinase 3 (MMP-3) and macrophage colony-stimulating factor (M-CSF) in patients with ankylosing spondylitis (AS).

METHODS

Serum levels of MMP-3 and M-CSF were measured in AS patients who did and did not receive infliximab treatment. These were compared with those of 28 healthy subjects.

RESULTS

In the group of AS patients not treated with biologics, both M-CSF and MMP-3 correlated with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) values, but not with each other. Logistic regression analysis showed that MMP-3 values were high in those with severely active disease. Infusions of infliximab in AS patients led to a significant decrease in the values of the BASDAI as well as the serum MMP-3, but no change in the serum M-CSF values.

CONCLUSION

MMP-3 and M-CSF are potentially useful markers of AS disease activity.

Differential expression and response to anti-TNFα treatment of infiltrating versus resident tissue macrophage subsets in autoimmune arthritis

Synovial macrophages play a pivotal role in the pathogenesis of chronic autoimmune arthritis by contributing to local inflammation and tissue damage and are therefore a primary target for therapeutic intervention. The aim of the present study was to investigate in more detail the relative contribution of different synovial macrophage subsets with potentially different inflammatory or anti-inflammatory functions by analysing the two most frequent forms of human autoimmune arthritis, spondyloarthropathy (SpA) and rheumatoid arthritis (RA). Both infiltrating macrophages from peripheral blood expressing myeloid-related proteins (MRP) 8 and 14, and resident tissue macrophages expressing CD163 were abundant in inflamed synovium. Whereas the global number of synovial macrophages was similar in both diseases, infiltrating macrophages were increased in the RA lining layer in contrast with resident tissue macrophages, which were more frequently observed in SpA. Soluble MRP8/MRP14 complexes, which were secreted locally in the joint during the infiltration process, were increased in the serum of arthritis patients and, in contrast with soluble CD163 shed from resident tissue macrophages, correlated well with global inflammatory parameters. Treatment in vivo with anti-TNFalpha had a rapid and pronounced effect on the infiltration of MRP-positive macrophages into tissues, as evidenced by histopathological analysis and serum MRP8/MRP14 levels. Taken together, these data support an important role for infiltrating versus resident tissue macrophages in human autoimmune synovitis and indicate that macrophage products such as soluble MRP8/MRP14 complexes are valuable biomarkers for the experimental and clinical monitoring of specific disease mechanisms in vivo.

Tumor necrosis factor α blockade treatment down-modulates the increased systemic and local expression of toll-like receptor 2 and toll-like receptor 4 in spondylarthropathy

OBJECTIVE

Abnormal host defense against pathogens has been implicated in the pathogenesis of spondylarthropathy (SpA), a disease characterized by abundant synovial infiltration with innate immune cells. Given the role of Toll-like receptors (TLRs) in activation of innate inflammation and the occurrence of TLR-dependent infections after tumor necrosis factor alpha (TNFalpha) blockade treatment, the present study was undertaken to analyze TLRs and their modulation by TNFalpha blockade in SpA.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from SpA and rheumatoid arthritis (RA) patients during infliximab therapy, and from healthy controls. TLR-2 and TLR-4 expression and TNFalpha production upon lipopolysaccharide (LPS) stimulation were analyzed by flow cytometry on different monocyte subsets. Synovial biopsy specimens from 23 SpA patients before and after infliximab or etanercept treatment, from 15 RA patients, and from 18 osteoarthritis (OA) patients were analyzed by immunohistochemistry.

RESULTS

Expression of TLR-4, but not TLR-2, was increased on PBMCs from patients with SpA, whereas both TLRs were increased in RA patients. TLR expression was particularly increased on the CD163+ macrophage subset. Infliximab reduced TLR-2 and TLR-4 expression on monocytes of SpA and RA patients, leading to lower levels than in controls and to impaired TNFalpha production upon LPS stimulation. In inflamed synovium, the expression of both TLRs and of CD163 was significantly higher in patients with SpA than in those with RA or OA. Paralleling the systemic effect, TLRs in synovium were down-regulated following treatment with infliximab as well as etanercept, indicating a class effect of TNFalpha blockers.

CONCLUSION

Inflammation in SpA is characterized by increased TLR-2 and TLR-4 expression, which is sharply reduced by TNFalpha blockade. These findings suggest a potential role of innate immunity-mediated inflammation in SpA and provide an additional clue regarding the mechanism of action as well as the potential side effects of TNFalpha blockade.

Rheumatoid factor and anticitrullinated protein antibodies in rheumatoid arthritis: diagnostic value, associations with radiological progression rate, and extra-articular manifestations

BACKGROUND

Autoantibodies such as rheumatoid factor (RF) and anticitrullinated protein antibodies can be detected in rheumatoid arthritis (RA) sera.

OBJECTIVE

To determine the diagnostic values of RF, anticitrullinated protein antibodies, and the shared epitope (SE), and their associations with radiological progression rates and extra-articular manifestations.

METHODS

Population 1 consisted of sera from 315 patients, consecutively sent for detection of anticitrullinated protein antibodies, of which 264 were used to determine the sensitivity and specificity of RF and of antibodies against three synthetic citrullinated peptides: peptide A (pepA), peptide B (pepB), and CCP2. Population 2 consisted of sera from 180 longstanding RA patients and was used to determine associations of RA associated antibodies and the SE with radiological progression rates and extra-articular manifestations. Antibodies to pepA and pepB were detected by line immunoassay, and antibodies to CCP2 by ELISA. HLA Class II typing was performed by LiPA.

RESULTS

In population 1, we defined adapted cut offs corresponding to a specificity of >/=98.5%. This yielded the following sensitivities: RF 12.8%; anti-pepA antibodies 63.6%; anti-pepB antibodies 54.2%; and anti-CCP2 antibodies 73.7%. In population 2, significant differences in radiological progression rates were found between positive and negative patients for different RA antibodies and the SE. RF, but not anticitrullinated protein antibodies or the SE, were more frequent in patients with extra-articular manifestations.

CONCLUSION

A valid comparison of RA associated antibodies shows superior sensitivity of the anticitrullinated protein antibodies compared with RF. The presence of RA associated antibodies and the SE are indicative for poorer radiological outcome, and presence of extra-articular manifestations is associated with RF but not with anticitrullinated protein antibodies.

Diagnostic classification of spondylarthropathy and rheumatoid arthritis by synovial histopathology: a prospective study in 154 consecutive patients

OBJECTIVE

To explore prospectively the value of synovial histopathology in comparison with the value of classic parameters for diagnostic classification of spondylarthropathy (SpA) and rheumatoid arthritis (RA) in patients with an atypical disease presentation.

METHODS

Synovial biopsy samples were obtained from 154 consecutive patients presenting for diagnostic evaluation; 67 patients fulfilled the classification criteria for RA, SpA, or other well-defined disease at the time of arthroscopy (cohort 1), and an additional 53 patients were classified after a full diagnostic reevaluation at 6 months (cohort 2). Synovial parameters with diagnostic value were identified in cohort 1 and were compared prospectively with classic diagnostic parameters in cohort 2.

RESULTS

Staining with anticitrulline, staining with monoclonal antibody 12A (recognizing HLA-DR shared epitope-human cartilage glycoprotein 39(263-275) complexes), and crystal deposition had positive predictive values (PPVs) for diagnosis of >90% in patients with an atypical disease presentation (cohort 2). Using these 3 parameters, a diagnosis was predicted by synovial histopathology in 39.6% of cohort 2 patients and turned out to be correct in 90.5% of these patients at 6 months of followup. Using a multiparameter model rather than single histopathologic parameters, even better results were obtained, with a diagnostic prediction in 79.2% of samples and a PPV of 81.0%. In comparison, a similar multiparameter model using classic diagnostic criteria rather than synovial histopathology performed poorly in cohort 2; the sensitivity was 56.6% and the PPV was 73.3%, with an inferior capacity to predict SpA. Especially for the presence of crystals and anticitrulline staining, the analysis of synovial tissue had a clear added value to the analysis of synovial fluid or serum in patients with an atypical presentation.

CONCLUSION

This proof-of-concept study indicates that synovial histopathology can contribute to the multiparametric diagnostic classification of inflammatory arthritis in patients with an atypical presentation.

Histological evidence that infliximab treatment leads to downregulation of inflammation and tissue remodelling of the synovial membrane in spondyloarthropathy

OBJECTIVE

To confirm and extend the immunopathological evidence of effects of infliximab on the synovium in active spondyloarthropathy.

METHODS

Synovial biopsies obtained in patients with spondyloarthropathy at baseline and week 12 were stained and scored by two independent observers. Two study populations were evaluated: I, a cohort of 10 patients treated with 5 mg/kg infliximab at week 0, 2, and 6, plus three placebo treated patients; and II, a pooled cohort of 20 patients fulfilling identical inclusion and exclusion criteria and treated with the same loading dose regimen.

RESULTS

In study population I, treatment with infliximab induced reduction in synovial lining layer thickness (p = 0.015), endothelial activation (E-selectin, p = 0.034), and inflammatory cell infiltration with neutrophils (p = 0.041), macrophages (p = 0.034), and T cells (p = 0.026), but not with B cells and plasma cells; no such trends were observed in the placebo treated patients. Besides confirming the highly significant downregulation of inflammation, analysis of cohort II showed structural changes such as normalisation of lining layer thickness (p = 0.030), reduction in the number of blood vessels (p = 0.039), and downregulation of follicular organisation (p = 0.050). No differences in histopathological response were observed between spondyloarthropathy subtypes.

CONCLUSIONS

Profound immunomodulatory changes in the synovium parallel the clinical benefit in patients with spondyloarthropathy treated with infliximab, independently of the subtype. The study provides histological evidence that TNF alpha blockade not only downregulates inflammation but also leads to tissue remodelling.

Specific antinuclear antibodies are associated with clinical features in systemic lupus erythematosus

OBJECTIVES

To study associations between antinuclear antibodies (ANA) and signs/symptoms in patients with systemic lupus erythematosus (SLE).

METHODS

A consecutive cohort of 289 patients with SLE was included; 235 fulfilled ACR criteria for SLE and were further analysed. ANA profiles were determined by line immunoassay and by indirect immunofluorescence on Crithidia luciliae. An extensive list of signs/symptoms was evaluated.

RESULTS

Five clusters of antibodies were defined by cluster analysis: 1-antibodies to SmB, SmD, RNP-A, RNP-C, and RNP-70k; 2-antibodies to Ro52, Ro60, and SSB; 3, 4, and 5-antibodies to ribosomal P, histones and dsDNA, respectively. Significant associations (p< or =0.01) were found between anti-RNP-70k, anti-RNP-A, anti-RNP-C and Raynaud's phenomenon, between anti-RNP-A, anti-RNP-70k and leucopenia, and between anti-RNP-A, anti-RNP-C and a lower prevalence of urine cellular casts. Anti-SSA, anti-SSB were associated with xerostomia, and anti-SSB with pericarditis. Antibodies to ribosomal P were associated with haemolytic anaemia, leucopenia, and alopecia. Patients with anti-dsDNA antibodies had a higher risk for cellular casts and a lower risk for photosensitivity. Antihistone antibodies were associated with arthritis.

CONCLUSIONS

In a large and consecutive cohort of patients with SLE, clusters of antibodies were identified. Previously reported associations of antibodies with symptoms were confirmed and new associations found.

Association of CD163+ macrophages and local production of soluble CD163 with decreased lymphocyte activation in spondylarthropathy synovitis

OBJECTIVE

Since CD163+ macrophages are selectively increased in spondylarthropathy (SpA) synovitis, we investigated the role of CD163+ macrophages in synovial inflammation.

METHODS

Synovial biopsy samples from 26 SpA and 23 rheumatoid arthritis (RA) patients were analyzed for macrophage and lymphocyte subsets. Synovial fluid (SF) samples were analyzed by Western blotting and enzyme-linked immunosorbent assay for soluble CD163 (sCD163) and by flow cytometry for lymphocyte activation. We also analyzed sCD163 in sera from 100 SpA patients, 23 RA patients, 20 healthy controls, and 20 SpA patients treated with infliximab. Polymorphism of haptoglobin (Hp), the CD163 ligand, was determined in 130 SpA and 23 RA patients.

RESULTS

CD163+ macrophages, but not CD68+ macrophages, were significantly increased in SpA versus RA synovium and in HLA-B27+ versus HLA-B27- SpA. Despite similar lymphocyte numbers, activated lymphocytes (CD69+) were significantly decreased in SpA versus RA patients, with an inverse correlation between CD163 and CD69 levels. Local production of sCD163 was evidenced by a 5-7-fold higher level of sCD163 in SF than in serum and by the correlation with synovial lining CD163+ macrophages in SpA. SF sCD163 levels correlated directly with global inflammation but correlated inversely with CD69+ SF T lymphocytes in the synovium. In contrast, serum sCD163 levels were only moderately increased, did not correlate with SF sCD163 levels or parameters of inflammation, and were unaffected by infliximab therapy. The distribution of Hp polymorphism was not altered in SpA and was not related to CD163 expression.

CONCLUSION

Increased numbers of CD163+ macrophages in SpA synovium and local production of sCD163 are associated with global inflammation as well as impairment of T cell activation, suggesting a dual role for CD163+ macrophages in SpA synovitis.

Tumour necrosis factor alpha independent disease mechanisms in rheumatoid arthritis: a histopathological study on the effect of infliximab on rheumatoid nodules

BACKGROUND

It has been suggested that the immunopathology of rheumatoid nodules parallels that of inflamed synovium in rheumatoid arthritis (RA).

OBJECTIVE

To analyse the effect of infliximab on the immunopathology of rheumatoid nodules in order to provide new insights into the relationship between synovial inflammation and rheumatoid nodules.

MATERIALS AND METHODS

Nodules were present at baseline in six patients with RA and after infliximab treatment in five patients, including paired nodules before and after treatment in three patients. In one patient, the nodule appeared during treatment. Paraffin sections were used for histological analysis. Frozen sections were stained by immunohistochemistry for cellular markers (CD3, CD4, CD8, CD16, CD20, CD68), blood vessels (CD146, vWF, alphavbeta3), and adhesion molecules (E-selectin, VCAM-1, ICAM-1).

RESULTS

No manifest immunopathological differences were found between the nodules before and after infliximab treatment. All nodules depicted the classical structure with a central necrotic zone, surrounding the palisade layer, and an outer connective tissue zone. Immunohistochemistry showed the presence of CD68+ and CD16+ macrophages in the palisade and the connective tissue zone, as well as a small number of CD3+, CD4+ T lymphocytes in the perivascular areas. Small vessels were seen in the connective tissue and were sometimes positive for the neovascularisation marker alphavbeta3. They expressed no VCAM-1, E-selectin weakly, but ICAM-1 strongly. ICAM-1 was also strongly expressed on palisade cells.

CONCLUSIONS

Despite an improvement of articular symptoms, infliximab treatment had no distinct effect on the histopathology of rheumatoid nodules, suggesting that different pathogenetic mechanisms mediate the two disease manifestations in RA.

Technical validation of cDNA based microarray as screening technique to identify candidate genes in synovial tissue biopsy specimens from patients with spondyloarthropathy

OBJECTIVES

To validate the use of cDNA based microarray on synovial biopsies by analysing the experimental variability due to amplification of RNA, reproducibility of the assay, heterogeneity of the tissue, and statistical analysis.

METHODS

Total RNA was extracted from three spondyloarthropathy (SpA) and three osteoarthritis (OA) synovial tissue biopsy specimens and from the peripheral blood mononuclear cells (PBMC) of four healthy donors. Exponential RNA amplification by SMART-PCR was compared with linear amplification. Reproducibility was tested by comparing different microarray systems and by performing duplicate experiments. Sample heterogeneity was assessed by comparing overall gene expression profiles, histopathology, and analysis of genes expressed in the synovium and normal PBMC. Statistical analysis using t test and Bonferroni adjustment was verified by permutation of class labels.

RESULTS

Gene expression was concordant in 12/14 (86%) cytokine/chemokine genes between both microarrays and different RNA amplification systems. When one microarray system was used, expressed genes were 78-95% concordant in duplicate experiments. Gene expression profiles had a higher degree of similarity between SpA synovium than between PBMC or OA synovium despite clear histopathological differences between synovial samples. Comparison of SpA synovium with OA synovium and with PBMC yielded 11 and 18 expressed transcripts, respectively; six were shared in both comparisons. Permutations of SpA and OA samples yielded only one expressed gene in 19 comparisons.

CONCLUSIONS

These data provide evidence that microarrays can be used for analysis of synovial tissue biopsies with high reproducibility and low variability of the generated gene expression profiles.

Rheumatoid factor, but not anti-cyclic citrullinated peptide antibodies, is modulated by infliximab treatment in rheumatoid arthritis

OBJECTIVES

To analyse the effect of infliximab on IgM rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibodies, and determine whether baseline autoantibody titres (IgM RF and anti-CCP antibodies) are associated with changes in acute phase reactants.

PATIENTS AND METHODS

62 patients with refractory RA were treated with infliximab combined with methotrexate. At baseline and week 30, serum samples were tested for IgM RF by two agglutination assays, and for anti-CCP antibodies by an ELISA. Percentage change in C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) was calculated.

RESULTS

At baseline and week 30 RF titres were reduced significantly during infliximab treatment (p<0.001 and p = 0.038, respectively), whereas anti-CCP antibodies were unchanged (p = 0.240). Baseline IgM RF titres, but not anti-CCP antibodies, correlated inversely with changes in CRP and ESR during treatment. Patients with a marked decrease in acute phase reactants had lower IgM RF titres than those with a smaller decrease in CRP and ESR; no significant differences were found for anti-CCP antibodies.

CONCLUSION

The differential effect of infliximab treatment on IgM RF and anti-CCP antibodies, and the different predictive value on changes in acute phase reactants during infliximab treatment support the existing evidence that RF and anti-CCP antibodies are independent autoantibody systems in RA.

Colon mucosa of patients both with spondyloarthritis and Crohn's disease is enriched with macrophages expressing the scavenger receptor CD163

BACKGROUND

Crohn's disease is associated with an increased number of macrophages in ileal and colonic mucosa. Data on macrophages in gut mucosa of patients with spondyloarthritis (SpA) are scarce.

OBJECTIVE

To investigate macrophages and other antigen presenting cells in gut mucosa from patients with SpA and Crohn's disease, given the relationship between both entities.

METHODS

Biopsy specimens from patients with SpA, Crohn's disease, ulcerative colitis, and from controls were immunohistochemically stained with different markers for macrophages and dendritic cells. Slides were scored semiquantitatively on a four point scale.

RESULTS

SpA and Crohn's disease were associated with large numbers of CD68+ macrophages. Colon mucosa of both patients with SpA and Crohn's disease, but not ulcerative colitis, showed increased numbers of macrophages expressing the scavenger receptor CD163.

CONCLUSIONS

Macrophages expressing the scavenger receptor CD163 are increased in colonic mucosa in SpA and in Crohn's disease, highlighting the relationship between these entities. The increased number of CD163+ macrophages in colon mucosa of patients with SpA suggests this is another argument for a role of macrophage scavenger receptors in this group of diseases.

Detection of major histocompatibility complex/human cartilage gp-39 complexes in rheumatoid arthritis synovitis as a specific and independent histologic marker

OBJECTIVE

Peptide 263-275 is the immunodominant epitope of human cartilage (HC) gp-39, a candidate autoantigen in rheumatoid arthritis (RA). We recently generated and characterized a monoclonal antibody (mAb) called 12A, which is directed against HLA-DR4/HC gp-39(263-275) complexes and inhibits specific T cell responses in vitro. The aim of the present study was to analyze whether presentation of the immunodominant epitope of HC gp-39 by shared epitope-positive synovial dendritic cells is a specific event in the development of chronic synovial inflammation in RA.

METHODS

Staining with mAb 12A was performed on synovium obtained from clinically swollen joints in 65 patients with RA and 67 non-RA controls and from joints without clinical effusion in 9 additional patients with RA.

RESULTS

Monoclonal antibody 12A staining was observed in the synovium of 40 of the 65 patients with RA. Histologically, expression of HC gp-39, lymphoid aggregates, CD3, and CD1a as well as the global inflammation score were higher in mAb 12A-positive RA synovium than in mAb 12A-negative synovium, indicating a follicular synovitis in these samples. Accordingly, mAb 12A stained dendritic cells in the close vicinity of lymphoid aggregates. No mAb 12A staining was detected in synovium obtained from RA joints without effusion. Clinically, there were no correlations between mAb 12A staining and clinical or biologic parameters in RA. However, positive staining was observed in 61.5% of the inflamed RA synovial samples compared with only 3.0% of the control samples (P < 0.001). This mAb 12A staining was not related to intracellular citrullinated peptides, which are another specific histologic marker for RA.

CONCLUSION

Presentation by synovial dendritic cells of the immunodominant epitope of HC gp-39, in the context of the shared epitope, is associated with characteristic histologic features of follicular synovitis and is highly specific for RA. This suggests a contribution to the autoimmune-related tissue inflammation and provides a new and independent tool for the immunopathologic diagnosis of RA.

Physiological levels of hydrocortisone maintain an optimal chondrocyte extracellular matrix metabolism

OBJECTIVE

To investigate the effects of physiological doses of hydrocortisone on synthesis and turnover of cell associated matrix (CAM) by human chondrocytes obtained from normal articular cartilage.

METHODS

Human articular cartilage cells were obtained from visually intact cartilage of the femoral condyles of five donors and maintained in culture for one week to reach equilibrium in accumulated CAM compounds. 0, 0.05, 0.20, and 1.0 micro g/ml hydrocortisone was added to the nutrient media during the entire culture period. Cells were liberated and levels of CAM aggrecan, type II collagen, and fibronectin, of intracellular IGF-1, IL1alpha and beta, and of their respective plasma membrane bound receptors IGFR1, IL1RI, and the decoy receptor IL1RII, were assayed by flow cytometry.

RESULTS

In comparison with controls, hydrocortisone treated chondrocytes, at all concentrations, expressed significantly higher plasma membrane bound IGFR1. Intracellular IGF-1 levels remained unchanged. Together with these changes, reflecting an increased ability to synthesise extracellular matrix (ECM) macromolecules, hydrocortisone treated cells expressed significantly higher amounts of the plasma membrane bound decoy IL1RII. Concurrently, intracellular IL1alpha and beta levels and membrane bound IL1RI were down regulated. Levels of CAM aggrecan, type II collagen, and fibronectin were significantly up regulated in the chondrocytes treated with hydrocortisone.

CONCLUSION

0.05 micro g/ml hydrocortisone treated chondrocytes had decreased catabolic signalling pathways and showed an enhanced ability to synthesise ECM macromolecules. Because IL1 activity was decreased and the expression of IL1RII decoy receptor enhanced, more of the ECM macromolecules produced remained accumulated in the CAM of the chondrocytes. The effects were obtained at doses comparable with physiological plasma levels of hydrocortisone in humans.