Ankylosing spondylitis and bowel disease

Clinical studies indicate an important role for bowel inflammation in ankylosing spondylitis and other spondyloarthropathies whereby two different aspects have to be considered. First, the gut inflammation is clinically and histologically closely related to Crohn's disease. Recent data on subclinical immune alterations confirm this relationship and suggest that spondyloarthropathy is a unique human model for studying early Crohn's disease. Second, bowel and peripheral joint inflammation are clinically, histologically and pathogenetically linked. The most important clinical implication of these observations is that targeted therapies for Crohn's disease could also be effective for intestinal as well as extra-intestinal disease manifestations in spondyloarthropathy, as evidenced by the recent studies on TNF-alpha blockade. Unravelling the gut-synovium axis in spondyloarthopathy could also contribute to the identification of new therapeutic targets. Finally, assessment of subclinical gut inflammation by histology, serology and genetics could contribute to the stratification of individual patients in subgroups with an optimal response to specific therapeutic interventions.

Influence of polysulphated polysaccharides and hydrocortisone on the extracellular matrix metabolism of human articular chondrocytes in vitro

OBJECTIVE

To evaluate the influence of hydrocortisone and two polysulphated polysaccharides (xylosan polysulphate and chondroitin polysulphate) on the extracellular matrix metabolism of chondrocytes cultured in gelled agarose.

METHODS

Isolated chondrocytes from normal femoral cartilage of the knee joints of 7 donors were cultured in gelled agarose to maintain their differentiated phenotype. After two weeks of culture, hydrocortisone (0.2 microgram/ml), xylosan polysulphate (10 micrograms/ml) and chondroitin polysulphate (10 micrograms/ml) were added to the culture media supplemented with or without interleukin (IL)-1 beta. After one week of incubation, the cells were liberated from the agarose with agarase. Isolated cells were labelled with antibodies against aggrecan and type II collagen, as well as biotinylated hyaluronic acid binding protein to analyse the extracellular matrix (ECM) molecules in the cell-associated matrix (CAM). The levels of matrix metalloproteinase (MMP)-1, -3, and -13, as well as tissue inhibitor of metalloproteinase (TIMP)-1 and -3 were determined after the cells had been permeabilised and stained with the appropriate antibodies. Triplicate samples were analysed with flow cytometry.

RESULTS

IL-1 beta decreased the accumulation of aggrecan, hyaluronan and type II collagen in the CAM and increased intracellular MMP-1, -3 and -13 at a concentration of 100 pg/ml. Xylosan polysulphate and chrondroitin polysulphate restored the expression of these CAM molecules in these IL-1 beta-treated cultures. Hydrocortisone stimulated the accumulation of CAM aggrecan and hyaluronan whether or not under the exposure to IL-1 beta. Intracellular MMP-1, -3, -13 and TIMP-1 and -3 of IL-1 beta-treated cells was downregulated after treatment with hydrocortisone.

CONCLUSION

Both hydrocortisone and the two polysulphated polysaccharides could stimulate the accumulation of CAM macromolecules of IL-1 beta-treated chondrocytes. This effect probably resulted in part from the downregulation of MMPs. These agents showed cartilage structure modifying effects in vitro.

Immune linkages between inflammatory bowel disease and spondyloarthropathies

Gut involvement is a prominent feature of spondyloarthropathy (SpA). Analysis of immune alterations of the gut in SpA have shown two distinct aspects. On the one hand, gut inflammation in SpA seems closely related with gut inflammation seen in Crohn disease. On the other hand, gut inflammation in SpA is associated with peripheral joint inflammation. Recent studies have provided new insights into this gut-synovium axis. First, there is little new evidence to support the concept of viable microbial pathogens recirculating to the joint. In contrast, it seems likely that both bacterial antigens and reactive T cell clones home to the joint, and that adhesion molecules such as the beta7 integrins and VAP1 play an important role in this process. Second, there is increasing evidence that the different disease localizations in SpA are characterized by alterations of the innate immune system, which contribute to a breakdown of the immune tolerance and the creation of an inflammation-prone environment. Mediators of the innate immune system, such as scavenger receptors, interleukin-10 (IL-10), and tumor necrosis factor alpha (TNF-alpha), may therefore be interesting targets for therapeutic intervention, as illustrated by the effect of TNF-alpha blockade in SpA.

Systems to assess the progression of finger joint osteoarthritis and the effects of disease modifying osteoarthritis drugs

Our objective was to assess the progression of osteoarthritis (OA) using scoring systems based on the anatomical changes recorded in the finger joints on standard radiographs and to test how far these scoring systems could be used to evaluate the effects of candidate "disease modifying osteoarthritis drugs" (DMOAD). The appearance and growth of osteophytes, narrowing of the joint space and subchondral bone changes allowed the classic OA-associated anatomical lesions to be used to score the progression of finger joint OA. Progression of OA in the finger joints was also assessed by the their evolution through previously described and predictable anatomical phases on standard X-rays. These phases were characterised by complete loss of the joint space preceding or coinciding with the appearance of subchondral cysts eroding the entire subchondral plate, and have been described in "inflammatory" or "erosive" OA. The erosive episodes were followed by processes of remodelling. In order to interfere with the progression of osteoarthritis, two chondroitin sulphates with possible DMOAD effects were used in two series of patients with OA of the finger joints. The patients were included in two separate randomised, double-blind placebo-controlled trials: 46 of them received chondroitin polysulphate and 34 received chondroitin sulphate. Eighty-five patients were kept on placebo medication and were used as controls. All 165 patients were followed for 3 years. Posteroanterior X-rays of the metacarpophalangeal and interphalangeal (IP) finger joints were obtained at the start of this prospective study and at yearly intervals thereafter. Almost 80% of the distal IP and 50% of the proximal IP were affected at study entry. In approximately 40% of the patients the classic picture of OA of the IP joints was complicated by manifest erosive OA changes. The two systems to score the progression of OA (Anatomical Lesion and Anatomical Phase Progression Score System) showed definite progression within 3 years of follow-up, especially in the IP joints. When compared with the placebo controls, none of the chondroitin sulphates prevented OA from occurring in previously normal finger joints. However, when the classic OA-associated anatomical lesions were considered, OA was less progressive in both active treatment groups. Furthermore, fewer patients from both chondroitin sulphate- and chondroitin polysulphate-treated groups developed "erosive" osteoarthritis. In conclusion, conventional radiographs can be used to assess the morbidity and progression of hand OA. The systems used to score the progression of finger joint OA allowed the DMOAD effects of both chondroitin sulphates to be evaluated. The data recorded during these pilot studies should help investigators to design future long-term clinical experiments.

Macrophages expressing the scavenger receptor CD163: a link between immune alterations of the gut and synovial inflammation in spondyloarthropathy

The objective of this study was to investigate CD163+ macrophages in the synovial membrane of patients with spondyloarthropathy (SpA). Immunohistochemistry was performed on synovium of 17 SpA and 18 rheumatoid arthritis (RA) patients, on colonic biopsies of 16 SpA patients and ten healthy controls, and on paired synovial biopsies of eight SpA patients, before and after anti-TNFalpha therapy. Phenotype and cytokine production were analysed by flow cytometry. CD163+ macrophages were increased in the synovial lining and sublining in SpA versus RA, as well as in colonic lamina propria in SpA versus controls. The number of CD163+ macrophages in the synovial sublining correlated with C-reactive protein levels and erythrocyte sedimentation rate. Paralleling the increase of CD163, HLA-DR was increased in the synovial lining and sublining of SpA. In contrast, the co-stimulatory molecules CD80 and CD86 and the dendritic cell markers CD1a and CD83 were scarce in SpA synovium. Flow cytometry indicated that CD163+ macrophages expressed high levels of HLA-DR and could produce in vitro tumour necrosis factor alpha (TNFalpha) but not interleukin-10 (IL-10). Finally, anti-TNFalpha therapy in vivo induced a decrease of CD163+ macrophages in the synovial lining and sublining. In conclusion, macrophages expressing the scavenger receptor CD163 are increased in synovium and in colonic mucosa in SpA, highlighting the relationship between joint and gut in this disease. The correlation with inflammatory parameters, the expression of HLA-DR, the production of TNFalpha but not IL-10, and the reduction by anti-TNFalpha therapy support a role for CD163+ macrophages in the synovial inflammation in SpA.

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

BACKGROUND

In a pilot study, the anti-tumour necrosis factor alpha 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.

Dynamic T cell receptor clonotype changes in synovial tissue of patients with early rheumatoid arthritis: effects of treatment with cyclosporin A (Neoral)

OBJECTIVE

To study T cell receptor (TCR) repertoire changes in synovial membrane over a 16 week period in patients with early rheumatoid arthritis (RA); and to study the influence of cyclosporin A (CSA) on TCR repertoire in a subgroup of these patients.

METHODS

Synovial tissue biopsies and paired blood samples were obtained from 12 patients with early RA at 2 time points. Seven patients were treated with CSA (Neoral-Sandimmun, 3 mg/kg/day) and 5 patients with placebo for 16 weeks. TCR V gene repertoires were analyzed by semiquantitative PCR-ELISA. CDR3 spectratyping and sequence analysis was used to compare TCR clonotype distributions.

RESULTS

TCR-specific mRNA was detected in all synovial tissue biopsies at the first sampling, but in only 8/12 biopsies 16 weeks later (4/7 CSA group, 4/5 placebo group). Overrepresented TCR BV genes were found in biopsies of 10/12 patients at the first time point, and in 7/12 patients after 16 weeks (3/7 CSA, 4/5 placebo). CDR3 sequence analysis revealed dynamic repertoire changes with only a few persisting clonotypes in the synovial tissue of placebo controls. Persisting T cell clonotypes were more frequently found in the synovial tissue of CSA treated patients compared to the placebo group.

CONCLUSION

These data suggest a dynamic process of T cell recruitment in the joints of RA patients. This process, possibly due to activation and subsequent infiltration of new T cell clones, apparently is influenced by CSA treatment. Synovial tissue T cells were no longer detected after 16 weeks' CSA treatment in 3 patients. In the other CSA treated patients, new T cell clones infiltrated, while other clones were persistently represented in the joints. These data may have important consequences for the design of T cell targeted therapies for RA.

Control of extracellular matrix homeostasis of normal cartilage by a TGFbeta autocrine pathway. Validation of flow cytometry as a tool to study chondrocyte metabolism in vitro

OBJECTIVE

To validate flow cytometry as an experimental technique for the study of the homeostasis of the extracellular matrix (ECM) of human articular cartilage.

METHODS

Given the established insights in the relation between the transforming growth factor (TGF)-beta type II Receptor (TGF-betaRII)/TGF-beta auto/paracrine pathway, the intracellular levels of matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs), and the accumulation of ECM molecules in the ECM of articular cartilage, this metabolic pathway was used as a reference model to fulfill the objective. Chondrocytes were liberated from visually intact femoral condyle cartilage and cultured in gelled agarose to maintain their differentiated phenotype. After 2 weeks of culture, the chondrocytes were isolated from the agarose and flow cytometry was used to analyse the expression of TGF-betaRII on the plasmamembrane, the expression of TGFbeta1, MMP-1, MMP-3, TIMP-1 and TIMP-3 inside the cells, as well as the amounts of aggrecan, type II collagen and hyaluronan in the cell-associated matrix (CAM). The expression of the different substances was analysed with flow cytometry and reported as mean fluorescence intensity (MFI), which is due to the binding of FITC-labeled antibodies to their specific antigens. In addition, the effects of exogenous TGFbeta1 on the expression of these proteins was investigated on chondrocytes cultured in serum-free media. Enzyme Linked Immunosorbent Assay (ELISA) was performed to evaluate the MMP-1, MMP-3, TIMP-1 and MMP-1/TIMP-1 complex in the culture medium collected after the last 3 days of the culture period. The correlations between the data were analysed with the Spearman's test.

RESULTS

Exogenous TGF-beta1 increased the accumulation of aggrecan and hyaluronan in the CAM of chondrocytes and down-regulated the intracellular levels of MMP-1 and -3. TIMP-1 and -3 were increased after exposure to TGF-beta1. Baseline expression of TGF-betaRII on the plasmamembrane of normal human articular chondrocytes significantly correlated with the intracellular levels of TGFbeta1, TIMP-1 and TIMP-3. TGFbeta1 was correlated with TIMP-1, TIMP-3 and MMP-1. Aggrecan in the CAM was inversely correlated with the ratio of MMP-1 to TIMPs. In addition, there were correlations between TIMP-1 and TIMP-3, aggrecan and hyaluronan. ELISA also revealed the correlation between MMP-1 and TIMP-1 secreted by the chondrocytes into the nutrient medium. MMP-1/TIMP-1 complex was hardly found in the medium.

CONCLUSIONS

Some aspects of ECM metabolism of normal cartilage were evaluated by flow cytometry. Chondrocytes from normal human cartilage, when cultured in gelled agarose, showed correlations between the expression of TGF-betaRII/TGF-beta1 and the intracellular levels of TIMPs, indicating that TGF-beta autocrine pathway may contribute to homeostasis of the ECM in the normal cartilage. The relations between MMPs, TIMPs and the ECM molecules support that a physiological balance between MMPs and TIMPs results in a well-controlled matrix turnover in normal cartilage.

Randomized double-blind comparison of chimeric monoclonal antibody to tumor necrosis factor alpha (infliximab) versus placebo in active spondylarthropathy

OBJECTIVE

To confirm in a placebo-controlled trial the safety and efficacy profile of infliximab in short-term treatment of patients with active spondylarthropathy (SpA).

METHODS

Forty patients with active SpA were randomly assigned to receive an intravenous loading dose (weeks 0, 2, and 6) of 5 mg/kg infliximab or placebo. Evaluations for efficacy and safety were performed at weeks 1, 2, 6, 8, and 12. The primary end points of this study were the improvements in patient and physician global assessments of disease activity on a 100-mm visual analog scale.

RESULTS

Both primary end points improved significantly in the infliximab group compared with the baseline value, with no improvement in the placebo group. As early as week 2 and sustained up to week 12, there was a highly statistically significant difference between the values for these 2 end points in the infliximab versus the placebo group. In most of the other assessments of disease activity (laboratory measures, assessments of specific peripheral and/or axial disease), significant improvements were observed in the infliximab group compared with the baseline value and compared with placebo. Minor adverse events not causing discontinuation were equally observed in both treatment groups. There was one severe drug-related adverse event, in which a patient developed disseminated tuberculosis.

CONCLUSION

Tumor necrosis factor alpha blockade with infliximab in patients with active SpA was well tolerated and resulted in significant clinical and laboratory improvements in this short-term, placebo-controlled study. However, the occurrence of tuberculosis in one patient necessitates strict inclusion criteria and long-term followup.

Detection and identification of antinuclear antibodies (ANA) in a large and consecutive cohort of serum samples referred for ANA testing

OBJECTIVE

To provide data on (a) the probability of detecting antinuclear antibodies (ANA) in a large and consecutive cohort of serum samples referred for ANA testing and (b) the probability of detecting more specific antinuclear reactivities (anti-DNA and anti-extractable nuclear antigens (anti-ENA)) in serum samples with a positive screening test (indirect immunofluorescence on HEp-2 cells).

METHODS

Serum samples from 10 550 consecutive patients sent to the laboratory for ANA detection were analysed. In ANA positive serum samples (23.5% of referred serum samples), ANA were identified by indirect immunofluorescence on Crithidia, by immunodiffusion, and by line immunoassay. Because anti-SSA antibodies were the most frequently identified ANA, sensitively detected by line immunoassay, additional immunoassays were developed to confirm the specificity of the line immunoassay result.

RESULTS

At least one fine reactivity could be identified in 21.1% of ANA positive serum samples: anti-dsDNA in 3.2%; anti-ENA (anti-SSA 10.5%, anti-SSB 6.7%, anti-RNP 2.7%, anti-Sm 1.8%, anti-Scl70 1.2%, anti-Jo-1 0.2%) in 15.8%, rRNP and anti-Cenp-B in respectively 0.5% and 4.0%. Multiple reactivities were found in 7.9%. For anti-ENA antibodies, line immunoassay was more sensitive than immunodiffusion (15.4% v 7.7%; p<0.0001). The sensitive detection of anti-SSA antibodies by line immunoassay was confirmed by additional assays.

CONCLUSIONS

The data from this analysis are useful in estimating the probabilities of detecting specific ANA. Line immunoassay was shown to be a sensitive test for the detection of anti-ENA antibodies.

Gut mucosal T cell lines from ankylosing spondylitis patients are enriched with alphaEbeta7 integrin

OBJECTIVE

An intriguing link between gut and synovial inflammation exists in patients with spondyloarthropathy (SpA), illustrated by the high frequency of microscopically inflammatory gut lesions observed in these patients. We hypothesise that aberrant homing of mucosal T cells might play a role in the induction/perpetuation of arthritis in SpA. Here, we analyse the expression of the homing molecules alpha4beta7 and alphaEbeta7 on mucosal T cells from patients with ankylosing spondylitis (AS) and controls, in view of the critical role of these receptors in the homing of mucosal lymphocytes.

METHODS

Colonic biopsy specimens were obtained from patients with AS (n = 23) and controls (n = 30). Biopsy specimens were immunostained, treated for extraction of intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) or cultured in the presence of IL-2. The expression of the beta7 integrins was investigated.

RESULTS

In situ no differences were observed in alphaEbeta7 and alpha4beta7 integrin expression in isolated IEL and LPL, whether determined by flow cytometry or by immunohistochemical staining. In gut mucosal T cell lines, alphaEbeta7 expression was significantly higher in the mucosa of patients with AS compared with controls. Alpha4beta7 was highly expressed on T cells in both groups studied. Mucosal T cells either expressed only the alpha4beta7 integrin or co-expressed the alpha4beta7 and alphaEbeta7 integrins. Almost none of them expressed only the alphaEbeta7 integrin.

CONCLUSION

In gut mucosal T cell lines from patients with AS an increased expression of alphaEbeta7 was observed.

Specific presence of intracellular citrullinated proteins in rheumatoid arthritis synovium: relevance to antifilaggrin autoantibodies

OBJECTIVE

To investigate the presence of citrullinated proteins in the synovial membrane of patients with rheumatoid arthritis (RA) and controls, and to analyze a possible relationship with antifilaggrin autoantibody (AFA) reactivity.

METHODS

Synovial biopsy samples were obtained from 88 consecutive patients undergoing needle arthroscopy for knee synovitis associated with RA (n = 36), spondylarthropathy (n = 35), osteoarthritis (n = 9), or other diagnoses (n = 8). Tissue sections were stained with 2 different anticitrulline polyclonal antibodies and an antifilaggrin monoclonal antibody (mAb). The phenotype of citrulline-positive cells and the colocalization with affinity-purified AFA were investigated by double immunofluorescence on frozen sections.

RESULTS

Studies with the first antibody showed that citrulline is expressed intracellularly in the lining and sublining layers of RA synovial tissue. Staining with the second antibody, monospecific for proteins containing modified citrulline, and with anti-inducible nitric oxide synthetase confirmed the presence of citrullinated proteins rather than free citrulline in the synovium. Citrulline-positive cells were detected in 50% of the RA patients (18 of 36) but in none of the controls (0 of 52). The anticitrulline reactivity colocalized with affinity-purified AFA reactivity, although stainings with the antifilaggrin mAb indicated the absence of filaggrin in the synovium.

CONCLUSION

Intracellular citrullinated proteins, which are not recognized by an antifilaggrin mAb, are expressed in RA but not in control synovium. The high specificity of this finding and the colocalization with AFA reactivity boost the interest in citrullinated proteins as possible triggers of autoimmune responses in RA. Moreover, this is the first description of a specific histologic marker for RA synovium.

The proportion of Th1 cells, which prevail in gut mucosa, is decreased in inflammatory bowel syndrome

T lymphocytes and their cytokines have an important role in the regulation of immune responses in the gut and in the pathogenesis of intestinal inflammation such as in Crohn's disease. The aim of this study was to analyse the Th1/Th2 cytokine profile (IFN-gamma, IL-2, IL-4 and IL-10) in intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) in Crohn's disease (CD) and ulcerative colitis (UC) in relation to healthy controls (C). Colonic and ileal biopsy specimens were obtained from controls (n = 13) and patients with CD (n = 32). Colonic biopsies were obtained from patients with UC (n = 11). Intracytoplasmic IFN-gamma, IL-2, IL-4 and IL-10 were determined by flow cytometry after PMA-ionomycin stimulation in IEL and LPL. In colonic LPL, a significant proportional decrease of IFN-gamma and IL-2 producing CD3+ cells was observed in patients with CD and UC compared to controls. In ileal LPL, a similar tendency was found although differences were not significant. In IEL no differences in cytokine profiles could be observed. Flow cytometric analysis of intracytoplasmic cytokines at single cell level showed a proportional decrease of IFN-gamma and IL-2 producing T cells in colonic lamina propria in patients with inflammatory bowel disease.

Culture of chondrocytes in alginate surrounded by fibrin gel: characteristics of the cells over a period of eight weeks

OBJECTIVE

To produce tissue engineered cartilage by human articular chondrocytes in vitro for further use in in vivo manipulations for the treatment of cartilage defects.

METHODS

Human articular chondrocytes were cultured in 0.5%, 1.0%, and 2.0% of alginate for up to four weeks. The optimal concentration of an alginate matrix for cell replication and for aggrecan synthesis by chondrocytes was determined. DNA content in the different culture conditions was measured after two and four weeks. Aggrecan synthesis rates and accumulation in the surrounding extracellular matrix were assessed by [(35)S]sulphate incorporation after the same periods of culture. To follow the outgrowth of chondrocytes from the alginate beads, chondrocytes were cultured for four weeks in 0.5 or 1.0% alginate surrounded by 0.25 or 0.5% fibrin gel. DNA content of each culture was measured after different culture periods. Finally, human chondrocytes in 1.0% alginate beads were embedded in 0.5% fibrin gel for eight weeks. Immunohistochemical analysis for aggrecan, type I and II collagen was performed weekly.

RESULTS

At two weeks the DNA content in each culture significantly increased in 0.5 and 1.0% alginate cultures in comparison with baseline values. This increase continued until week 4 at the three alginate concentrations. Aggrecan synthesis at two weeks was highest in 0.5 and 1.0% alginate cell cultures. At four weeks aggrecan synthesis rates decreased independently of the alginate concentrations. Aggrecan mainly accumulated in the interterritorial matrix. Proliferation of chondrocytes in alginate and outgrowth of these cells in the surrounding fibrin gel were evident throughout the culture period. The accumulation of aggrecan and type II collagen around the cells, in alginate as well as in fibrin gel, gradually increased over the culture period. Type I collagen appeared after six weeks in alginate and in the surrounding fibrin.

CONCLUSION

Human chondrocytes proliferate in this culture system, show an outgrowth into the surrounding fibrin, and synthesise a cartilage-like matrix for up to eight weeks.

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

OBJECTIVES

To evaluate the effect of anti-TNFalpha 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)gamma 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 IFNgamma (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 IFNgamma 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. TNFalpha blockade induced restoration of the Th1 cytokines, resulting in a normal cytokine balance. These data confirm the effect of anti-TNFalpha on the immune changes in SpA, and provide insights into the mechanisms involved in TNFalpha blockade.

The Belgian-Flemish version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ)

We report herein the results of the cross-cultural adaptation and validation into the Belgian-Flemish language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Belgian-Flemish CHAQ was fully validated with 3 forward and 3 backward translations, while the Belgian-Flemish CHQ was equal to the Dutch version and revalidated in this study. The French version of both CHAQ and CHQ was exactly the same as the one used in France. A total of 199 subjects were enrolled: 53 patients with JIA (11% systemic onset, 40% polyarticular onset, 13% extended oligoarticular subtype, and 36% persistent oligoarticular subtype) and 146 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the polyarticular onset, and extended oligoarticular subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Belgian-Flemish version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.

Evaluation of chondrocyte cell-associated matrix metabolism by flow cytometry

OBJECTIVE

To analyze human articular chondrocyte cell-associated matrix aggrecan, hyaluronan (HA) and type II collagen metabolism using flow cytometry, and to compare the results obtained for aggrecan with classic(35)Sulfate incorporation methods and an enzyme linked immunosorbent assay (ELISA).

DESIGN

Human articular chondrocytes obtained from five donors were cultured in gelled agarose and tested for their response to different concentrations of interleukin-1beta (IL-1beta). Synthesis and distribution of aggrecan in the cell-associated matrix (CAM), in the interterritorial matrix and in the nutrient medium of the chondrocytes in culture were analyzed using(35)Sulfate incorporation. The results were expressed as pg SO(4)incorporated in aggrecan per 1 x 10(6)cells/h. Flow cytometry with FITC-conjugated monoclonal antibodies against aggrecan and type II collagen, and with the biotinylated hyaluronic acid binding protein (b-HABP), was used to investigate the synthesis and accumulation of aggrecan, type II collagen and HA in the CAM of the cultured cells. The packing of these macromolecules in the CAM of the chondrocytes was assessed by measuring the mean fluorescence intensity (MFI) of the cell sample due to the binding of the specific monoclonal antibodies or b-HABP used. ELISA was used in parallel to quantify CAM aggrecans after these macromolecules were brought into solution with guanidinium chloride. Detection of aggrecan by flow cytometry was compared with(35)S-incorporation in chondrocytes from two subjects and with ELISA in a further two donors.

RESULTS

IL-1beta suppressed aggrecan synthesis by chondrocytes in agarose. An IL-1beta dose-dependent suppression of(35)S-aggrecan in the CAM reflected the changes in the interterritorial matrix. IL-1beta-induced aggrecan breakdown was followed by a rise in(35)S-aggrecan metabolites in the incubation media of the cells in culture. Flow cytometry and ELISA confirmed this decreased accumulation of aggrecan in the CAM of the chondrocytes. The results obtained with flow cytometry were closely related to those obtained with ELISA.(35)S-incorporation, on the other hand, indirectly measures the glycosaminoglycan content of the aggrecan and does not necessarily reflect the absolute amount of aggrecan molecules. Therefore, the effects of IL-1beta on cell-associated aggrecan, where assessed with(35)S-incorporation, did not correlate with the results of the flow cytometric assays. Flow cytometry enabled the detection of an impaired synthesis and accumulation of HA and of type II collagen in the CAM of the cultured chondrocytes. IL-1beta-induced changes in CAM aggrecan and hyaluronan closely agreed.

CONCLUSIONS

Flow cytometry offers an efficient tool to study the metabolism of the chondrocyte CAM. The MFI has been used as a parameter to quantify the ECM molecules in the CAM.

Flow cytometric analysis of gut mucosal lymphocytes supports an impaired Th1 cytokine profile in spondyloarthropathy

OBJECTIVE

To quantify the fraction of gut mucosal lymphocytes expressing the T helper type 1 (Th1) cytokines, interferon gamma (IFNgamma) and interleukin (IL)2, and the Th2 cytokines, IL4 and IL10, at the single cell level in patients with spondyloarthropathy (SpA) in comparison with healthy controls.

METHODS

An improved extraction protocol was used for the enrichment of intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) from colonic and ileal biopsy specimens obtained from patients with SpA (n=20) and healthy controls (n=13). After stimulation with phorbol ester/ionomycin, expression of the intracellular cytokines IFNgamma, IL2, IL4, and IL10 was determined in CD3+, CD3+CD8+ and CD3+CD8- T cells by flow cytometry.

RESULTS

In colonic LPLs, a significant decrease in IFNgamma-producing CD3+ cells was observed (p=0.02) in patients with SpA. In the CD3+CD8- subset, the proportion of cells producing IFNgamma and IL2 was decreased in patients with SpA (p=0.021 and p=0.027 respectively). In ileal LPLs, the percentage of IL10-producing CD3+CD8- cells was significantly increased (p=0.046).

CONCLUSION

An impaired Th1 cytokine profile is observed in gut mucosal lymphocytes from patients with SpA. This adds to the existing evidence that the gut mucosal immune apparatus is involved in the pathogenesis of SpA.

Biological freezing of human articular chondrocytes

AIM

To preserve viable, metabolically active chondrocytes cultured in alginate beads at -196 degrees C for further use in in vitro and in vivo studies.

METHODS

Human articular chondrocytes were isolated from femoral condyles within 24 h post mortem. To optimize the biological freezing procedure, the chondrocytes were control-rate frozen in different concentrations of dimethyl sulfoxide (DMSO) in Dulbecco's MEM supplemented with 10% FCS before being thawed and the cell viability was determined by Trypan Blue exclusion test. To investigate the effect of control-rate freezing on chondrocyte metabolism, control-rate frozen chondrocytes in 5% DMSO were thawed and cultured in gelled agarose for 2 weeks. Non-frozen chondrocytes cultured in agarose served as controls. Furthermore, human articular chondrocytes were cultured in 2% alginate beads for 2 weeks after which the beads were incubated with 5% DMSO for 0 h, 2.5 h, 5 h and 10 h and frozen at -196 degrees C. Non-frozen alginate beads containing chondrocytes and incubated with 5% DMSO served as a control. After 2 weeks in culture, chondrocytes in agarose or in alginate were sulfated with 10 microCi(35)SO(4)/ml for 48 h. The total production of aggrecans, and the aggrecan subtypes, were subsequently determined.

RESULTS

Five percent DMSO in the culture medium was the optimal condition to control-rate freeze and recover viable and functional isolated chondrocytes. Total aggrecan synthesis of control-rate frozen chondrocytes cultured in gelled agarose was not significantly reduced when compared with control cells. The proportion of aggrecan in the aggregate form of control-rate frozen chondrocytes kept in agarose remained unaltered. Chondrocytes, control-rate frozen in the alginate matrix, showed a 0-30% decrease in total aggrecan synthesis rates in culture when compared with the non-frozen chondrocytes. The optimal pre-incubation time of the alginate beads with 5% DMSO was 5 h, without any change in aggrecan synthesis rates when compared with the control situation. Shorter pre-incubation times resulted in an insufficient diffusion of DMSO into the beads and in cell death. There was no difference in the synthesis of the different aggrecan subtypes between frozen and non-frozen chondrocytes in alginate.

CONCLUSION

Human articular chondrocytes can be stored at -196 degrees C for 24 h without important decreases in their aggrecan synthesis rates when control-rate frozen as a cell suspension in 5% DMSO. Proportions of the aggrecan subtypes (monomers, aggregates) synthesized by chondrocytes cultured in agarose remained unchanged. The control-rate freezing procedure in the alginate beads pre-incubated with 5% DMSO for 5 h produced no decrease in total aggrecan synthesis rates and no change in the synthesized aggrecan subtypes. Further experiments have to confirm the suitability of this freezing method for long-term storage of chondrocytes allowing us to set up a 'chondrocyte' bank for further use in in vitro and in vivo manipulations.