Detection of Borrelia burgdorferi by polymerase chain reaction in synovial membrane, but not in synovial fluid from patients with persisting Lyme arthritis after antibiotic therapy

OBJECTIVES—To identify possible sites of bacterial persistence in patients with treatment resistant Lyme arthritis. It was determined whether Borrelia burgdorferi DNA may be detectable by polymerase chain reaction (PCR) in synovial membrane (SM) when PCR results from synovial fluid (SF) had become negative after antibiotic therapy.
METHODS—Paired SF and SM specimens and urine samples from four patients with ongoing or recurring Lyme arthritis despite previous antibiotic therapy were investigated. A PCR for the detection of B burgdorferi DNA was carried out using primer sets specific for the ospA gene and a p66 gene of B burgdorferi.
RESULTS—In all four cases, PCR with either primer set was negative in SF and urine, but was positive with at least one primer pair in the SM specimens. In all patients arthritis completely resolved after additional antibiotic treatment.
CONCLUSIONS—These data suggest that in patients with treatment resistant Lyme arthritis negative PCR results in SF after antibiotic therapy do not rule out the intraarticular persistence of B burgdorferi DNA. Therefore, in these patients both SF and SM should be analysed for borrelial DNA by PCR as positive results in SM are strongly suggestive of ongoing infection.

Keywords: Lyme arthritis; polymerase chain reaction; synovial membrane; synovial fluid     

Initiation and perpetuation of rat adjuvant arthritis is inhibited by the anti-CD2 monoclonal antibody (mAb) OX34

OBJECTIVE—The purpose of this study was to investigate the therapeutic potential of the anti-CD2 mAb OX34 first with regard to bone protection in established rat adjuvant arthritis (AA) and secondly with regard to prevention of AA induction.
METHODS—Established AA was treated with dexamethasone (1 mg/kg body weight) for two days plus OX34 mAb or control mAb over three days (2 mg and then 1 mg) starting at different time points of the disease. For prevention studies animals were injected as above with mAb before induction of AA. Arthritis score (AS), hindpaw thickness, and body weight were blindly measured three times per week. Flow cytometry and hindpaw radiography were performed at the end of the study (day 29).
RESULTS—Treatment of early AA with OX34 mAb combined with dexamethasone but not dexamethasone plus control mAb dramatically suppressed established AA as assessed by AS and hind paw thickness (>65% and >80% reduction, respectively; p < 0.05). Most importantly, early treatment in the course of AA almost completely prevented bone destruction in established AA. When given before AA induction OX34 alone prevented the initiation of arthritis compared with controls (AS reduction 83-95%, p < 0.05). In addition, OX34 plus dexamethasone treatment resulted in depletion of CD4⁺ T cells but not CD8⁺ T cells. IL2R⁺ and CD45RC^-(`memory') T cells were significantly reduced.
CONCLUSIONS—Anti-CD2 mAb treatment prevents AA induction confirming the role of CD4⁺ T cells in the induction phase of AA. In addition, early OX34 plus dexamethasone treatment resulted in pronounced clinical improvement and joint protection. OX34 treatment therefore inhibits the initiation and the perpetuation of rat AA.

     

TCRβ spectratyping in RA: evidence of clonal expansions in peripheral blood lymphocytes

OBJECTIVE—To compare the TCRβ repertoire of peripheral blood CD8 enriched (CD8+) and depleted (CD8−) T cells in rheumatoid arthritis (RA) patients and controls using CDR3 length analysis (spectratyping).
METHODS—CD8+ and CD8− T cells were separated from 14 RA patients and 12 controls, using magnetic beads coated with anti-CD8 monoclonal antibodies. cDNA was prepared as the template for amplification with 22 Vβ-Cβ primer pairs. The products were resolved by electrophoresis in an ABI373 sequencer using GENESCAN software. Expansions were identified as dominant CDR3 lengths, where the area underlying the corresponding peak exceeded the sum of the areas of the two adjacent peaks. This method was validated by sequencing 10 samples displaying dominant peaks. The expansion frequencies in RA patients and controls were compared using the χ² test statistic.
RESULTS—Dominant peaks were evident in several Vβ families. They were more frequent in RA patients in both the CD8+ subset (RA normalised frequency 10.6; control normalised frequency 8.0; p=0.03) and the CD8− subset (RA normalised frequency 2.9; control normalised frequency 1.5; p=0.02). Sequencing of 10 samples exhibiting dominant peaks revealed an unequivocal clonal expansion in nine (90%).
CONCLUSIONS—RA patients exhibited a significantly increased frequency of T cell expansions both in the CD8+ and CD8− subsets. This phenomenon may reflect the proliferation of autoreactive cells, a non-specific expansion of memory T cells in response to pro-inflammatory cytokines or a defect of T cell regulation that predates the onset of RA and may itself predipose to disease.

Keywords: rheumatoid arthritis; T cell; clonal expansion     

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.

Keywords: T cells; adhesion molecules; rheumatoid nodules; rheumatoid synovium     

Ceramide, a mediator of interleukin 1, tumour necrosis factor α, as well as Fas receptor signalling, induces apoptosis of rheumatoid arthritis synovial cells

OBJECTIVES—To examine the effects of ceramide, which is a lipid second messenger of cell surface receptors, including tumour necrosis factor α (TNFα), interleukin 1 (IL1), and Fas receptors, on rheumatoid arthritis (RA) synovial cells.
METHODS—Synovial cells from RA patients and normal skin fibroblasts were cultured with cell permeable ceramide (C2-ceramide). Apoptosis was assessed by microscopic observation of morphological changes, nuclear staining, and DNA electrophoresis. DNA synthesis was examined by thymidine incorporation.
RESULTS—C2-ceramide induced reversible morphological changes of synovial cells such as cell rounding within four hours. Subsequently, irreversible nuclear changes characteristic to apoptosis were observed at 48 hours. DNA synthesis was not promoted. The addition of ceramide exerted similar effects on cultured dermal fibroblasts.
CONCLUSION—Ceramide induced apoptosis in RA synovial cells. Ceramide could be a second messenger specific for apoptosis of RA synovial cells.

Keywords: ceramide; apoptosis; rheumatoid arthritis     

Increased state of activation of CD4 positive T cells and elevated interferon γ production in pouchitis

Background—Immunoregulatory abnormalities of Tcells might be of importance in the pathogenesis of pouchitis afterileoanal pouch anastomosis (IAP).
Aims—To characterise T cell subsets, their stateof activation, and production of cytokines in inflamed and non-inflamedpouches in patients with ulcerative colitis (UC) and familialadenomatous polyposis (FAP). The influence of T cell activation onmucosal transformation was also studied.
Patients—Mucosal biopsy specimens were taken from42 patients with IAP (33 with UC and nine with FAP).
Methods—Mononuclear cells were isolated bystandard techniques and characterised by three colour flow cytometry.Interferon γ (IFN-γ) production was studied using the ELISPOT technique.
Results—In patients with UC with pouchitis therewas a significant increase in the CD4:CD8 ratio, expression ofactivation markers on CD3+ cells, and number of IFNγ producingmononuclear cells compared with patients with UC without pouchitis(CD4:CD8 ratio 1.3 (range 0.7-2.7) versus 0.6 (0.1-1.0), p=0.012). Inaddition, a positive correlation between increased crypt depth and thenumber of CD4+ cells (r=0.57) was shown.
Conclusion—The observed increase in activatedmucosal CD4+ T cells and IFN-γ production might lead to mucosaldestruction and crypt hyperplasia as seen in pouchitis.

Keywords:pouchitis; T cell activation; mucosaltransformation

     

Iron, lactoferrin and iron regulatory protein activity in the synovium; relative importance of iron loading and the inflammatory response

OBJECTIVES—To determine the ability of lactoferrin in rheumatoid arthritis (RA) synovial fluid to bind "free" iron, and to study the regulatory mechanisms therein that control iron homeostasis.
METHODS—"Free" iron was determined by the bleomycin assay and lactoferrin concentrations by enzyme linked immunosorbent assay. The activities of iron regulatory protein (IRP) and NF-κB in synovial fluid cells were assayed by mobility shift assay.
RESULTS—30% of synovial fluids contained "free" iron and in these, lactoferrin concentrations were significantly lower than in those with no "free" iron (p<0.01). Addition of exogenous lactoferrin consistently reduced the amount of "free" iron in positive synovial fluids. IRP activity in synovial cells did not correlate with synovial fluid iron concentrations but did correlate with NF-κB activation and with serum C reactive protein.
CONCLUSION—Lactoferrin may prevent iron mediated tissue damage in RA by reducing "free" synovial iron concentration when inflammatory stimuli have disregulated IRP mediated iron homeostasis.

Keywords: lactoferrin; rheumatoid arthritis; inflammation     

Antisense oligonucleotides targeting c-fos mRNA inhibit rheumatoid synovial fibroblast proliferation

OBJECTIVE—To determine whether antisense oligonucleotides targeting c-fos mRNA have the ability to inhibit the growth of interleukin 1 (IL1) stimulated fibroblast-like cells from the synovium in rheumatoid arthritis (RA).
METHODS—Fibroblast-like cells established from RA synovium were stimulated by IL1 with antisense or sense oligonucleotides complementary to c-fos mRNA, and the proliferation of these cells was determined by ³H-thymidine incorporation. Effect of antisense oligonucleotides on expression of activator protein 1 (AP1) activity was evaluated using electrophoretic mobility shift assay.
RESULTS—C-fos antisense oligonucleotides inhibited IL1 stimulated synovial fibroblast proliferation. The expression of AP1 activity induced by IL1 was suppressed by treatment with antisense oligonucleotides.
CONCLUSION—These results suggest the feasibility of antisense strategies designed to suppress c-fos expression as therapeutic agents for RA.

Keywords: antisense oligonucleotides; c-fos; activator protein 1; synovial fibroblasts     

Effect of a three month course of ciprofloxacin on the outcome of reactive arthritis

BACKGROUND—Treatment of reactive arthritis (ReA) with antibiotics has so far remained controversial. Eradication of the causative microbe appears logical, but short term antibiotic treatment has no beneficial effect on the outcome of ReA.
OBJECTIVE—To evaluate the effect of a three month course of ciprofloxacin on ReA.
METHODS—In a randomised, double blind, placebo controlled trial, between December 1992 and February 1996, 71 patients with acute ReA triggered by a gastrointestinal or a urogenital infection were randomly assigned to receive ciprofloxacin 500 mg or placebo twice daily for three months. Patients were assessed at study entry, at 6 weeks, 3 months, 6 months, and 12 months. Sixty two patients were valid for the efficacy analysis. The primary outcome measures were erythrocyte sedimentation rate, number of swollen joints, patients self assessment, and complete recovery.
RESULTS—Adverse events were mostly mild and occurred in both treatment groups. There were no statistically significant differences in any of the primary or secondary efficacy variables between the study groups at baseline or during the 12 month follow up. All primary outcome measures indicated that the condition of the patients improved during the study.
CONCLUSION—Both groups tended to recover. Ciprofloxacin, given as a three month course, had no advantage over placebo treatment.

     

Enrichment of differentiated CD45RBdim,CD27 – memory T cells in the peripheral blood,synovial fluid,and synovial tissue of patients with rheumatoid arthritis

Objective. To delineate in greater detail the phenotype of T cells that reside in the synovial tissue (ST) and synovial fluid (SF) of patients with rheumatoid arthritis (RA), in order to determine their precise differentiation status, and to determine whether the accumulation of these specific T cell subsets in these synovial compartments could be related to their capacity for transendothelial migration. Methods. Lymphocytes from normal subjects or from the peripheral blood (PB), ST, and/or SF of RA patients were phenotypically analyzed by flow cytometry. Normal PB CD4+ T cells were also characterized using an in vitro assay of transendothelial migration. Results. ST and SF were found to be enriched with memory (CD45RA-, CD45RO+, CD11a^bright, CD44^bright) and activated (CD69+) T cells. Moreover, ST and SF cells from RA patients were enriched in differentiated CD4+, CD45RB^dim, CD27- T cells, a subset of mature memory T cells that develops after prolonged antigenic stimulation. In addition, PB of some RA patients contained an increased number of CD4+, CD45RB^dim, CD27- T cells. The CD4+, CD11a^bright, CD44^bright memory T cells, which included the CD45RB^dim, CD27- more mature memory cells, exhibited an enhanced capacity for transendothelial migration that is likely to contribute to their enrichment in the rheumatoid synovium. Conclusion. RA patients manifest an increased number of mature memory T cells in the SF and ST, and some also have an increased number of these cells in PB that is likely to reflect chronic antigenic stimulation. The enrichment of these cells in the SF and ST reflects, in part, an enhanced capacity to migrate from the vascular space into inflamed tissue.     

Detection of oncostatin M in synovial fluid from patients with rheumatoid arthritis

OBJECTIVE—To measure oncostatin M (OSM) in synovial fluid from patients with rheumatoid arthritis (RA) and osteoarthritis (OA).
METHODS—20 samples of synovial fluid from patients with RA and 10 samples from patients with OA were examined using an OSM specific sandwich ELISA.
RESULTS—OSM was detected at concentrations ranging from 2.36 to 901.82 pg/ml in 18 (90%) of 20 samples of synovial fluid from RA patients. There was no detectable OSM in synovial fluid from OA patients. In the RA patients, the OSM concentration in synovial fluid correlated significantly with the synovial fluid white blood cell count (r=0.67, p<0.01), but not with other laboratory parameters of disease activity.
CONCLUSION—These findings suggest that OSM may contribute to joint inflammation in RA.

     

Quantitative assessment of the rheumatoid synovial microvascular bed by gadolinium-DTPA enhanced magnetic resonance imaging

OBJECTIVE—To examine the relation between rate of synovial membrane enhancement, intra-articular pressure (IAP), and histologically determined synovial vascularity in rheumatoid arthritis, using gadolinium-DTPA enhanced magnetic resonance imaging (MRI).
METHODS—Dynamic gadolinium-DTPA enhanced MRI was performed in 31 patients with knee synovitis (10 patients IAP study, 21 patients vascular morphometry study). Rate of synovial membrane enhancement was quantified by line profile analysis using the image processing package ANALYZE. IAP was measured using an intra-compartmental pressure monitor system. Multiple synovial biopsy specimens were obtained by a blind biopsy technique. Blood vessels were identified immunohistochemically using the endothelial cell marker QBend30 and quantified (blood vessel numerical density and fractional area).
RESULTS—Median blood vessel numerical density and fractional area were 77.5/mm² (IQR; 69.3-110.7) and 5.6% (IQR; 3.4-8.5) respectively. The rate of synovial membrane enhancement (median 2.74 signal intensity units/s, IQR 2.0-3.8) correlated with both blood vessel numerical density (r = 0.46, p < 0.05) and blood vessel fractional area (r = 0.55, p < 0.02). IAP did not influence the rate of enhancement.
CONCLUSIONS—Gadolinium-DTPA enhanced MRI may prove to be a valuable technique for evaluating drugs that influence angiogenesis.

Keywords: magnetic resonance imaging; rheumatoid arthritis; synovitis; vascularity     

Inactivation of antithrombin III in synovial fluid from patients with rheumatoid arthritis

OBJECTIVE—To investigate the thrombin inhibitory capacity of antithrombin III in the inflamed human joint.
METHODS—Thrombin inhibitory capacity was measured, using a kinetic spectophotometric method, in matched plasma and synovial fluid samples of patients with rheumatoid arthritis (n=22) and osteoarthritis (n=16), together with normal control plasma samples (n=13). In the same samples, the concentration of antithrombin III was also determined by the method of radial immunodiffusion. The combination of these measurements allowed the calculation of the specific thrombin inhibitory capacity of these samples.
RESULTS—An increased concentration of antithrombin III in rheumatoid compared with osteoarthritic synovial fluid was noted (p<0.05). However, there was a significant depression in the specific activity of antithrombin III in rheumatoid synovial fluid when compared with matched plasma samples (p<0.001) or with osteoarthritic synovial fluid (p<0.05).
CONCLUSION—In rheumatoid synovial fluid the thrombin inhibitory capacity of antithrombin III is disproportionately depressed relative to the concentration of antithrombin III, indicating the inactivation of antithrombin III in the rheumatoid joint.

Keywords: antithrombin III; thrombin; rheumatoid arthritis; synovial fluid     

T cell derived cytokines in psoriatic arthritis synovial fluids

OBJECTIVE—The aim of this study was to investigate the concentrations of T cell derived cytokines in the synovial fluids (SFs) of patients with psoriatic arthritis (PsA) in comparison with rheumatoid arthritis (RA) and osteoarthritis (OA).
METHODS—Th1 type cytokines (interleukin 2 (IL2), tumour necrosis factor β (TNFβ), and interferon γ (INFγ)) and Th2 type cytokines (IL4, IL10) were measured by means of enzyme linked immunosorbent assays.
RESULTS—IL2 was usually not detectable in any of the disease groups. TNFβ was found in 3 of 31 PsA SFs (mean (SEM) 11.1 (2.3) pg/ml) and in a significantly lower concentration than in 20 of the 40 RA SFs (42.2 (15.6) pg/ml; p < 0.002). INFγ was measurable in 2 of 10 PsA and 6 of 16 RA SFs (p > 0.05). IL4 was present at low concentrations in 4 of 22 PsA SFs (0.41 (0.8) pg/ml), and in 15 of 20 RA SFs (0.63 (0.09) pg/ml; p < 0.01). IL10 was found in 4 of 27 PsA SFs (12.3 (0.9) pg/ml) and in 27 of 32 RA SFs (37.3 (4.9) pg/ml; p < 0.0001). In all OA SFs cytokine concentrations were below the limit of detection.
CONCLUSION—The pattern of T cell derived cytokines in PsA SFs was similar to that of RA SFs. However, both the frequency and the concentrations of cytokines were lower in PsA SFs than in RA SFs, while OA SFs generally lacked any detectable T cell cytokines altogether. The presence of Th1 and Th2 cell derived cytokines in PsA SFs suggests the presence of activated T cells in the inflamed joint tissues and their participation in the immunoinflammatory events.

Keywords: psoriatic arthritis; rheumatoid arthritis; cytokines; T cells; synovial fluids     

Cartilage macromolecules in knee joint synovial fluid. Markers of the disease course in patients with acute oligoarthritis

OBJECTIVE—To investigate the development of chronic joint symptoms in patients presenting with acute oligoarthritis including knee joint synovitis with effusion and explore whether prognostic information can be derived from initial synovial fluid concentrations of aggrecan and cartilage oligomeric matrix protein (COMP) for development of chronic joint symptoms.
METHODS—Retrospective follow up of 25 patients identified in a bank of knee joint synovial fluids collected consecutively from patients presenting with knee joint synovitis and symptoms from at most three additional joints and in whom no diagnosis could be established at presentation.
RESULTS—The 10 patients who developed chronic joint symptoms were characterised by lower knee joint synovial fluid concentrations of aggrecan as well as lower aggrecan/COMP ratios (p<0.001) than the 15 patients who had a transient arthritis. No other clinical or laboratory differences between the groups were apparent at the time of presentation.
CONCLUSIONS—The synovial fluid content of aggrecan is a potential tool in acute arthritis for distinguishing patients with a benign disease course from those who will develop a chronic joint disorder.

     

Quality control of synovial fluid crystal identification

OBJECTIVE—To establish a quality assessment programme for the diagnosis of crystal arthropathies by synovial fluid (SF) microscopy.
METHODS—Three or four cytocentrifuge slides prepared from suitable patient SF specimens were distributed to 25-47 predominantly Finnish clinical laboratories once a year. Sodium urate crystals were included in every survey.
RESULTS—Returns for the years 1989-1996 were reviewed. Laboratories that participated in > four surveys made on an average one error a year (range 0.25-2). The error rate for specimens containing abundant crystals was acceptable but it increased considerably for specimens showing few crystals per microscope field. No laboratory characteristic predictive of successful performance was found.
CONCLUSION—Errors in quality assessment results for crystal identification were much more frequent than in the fields of, for example, clinical chemistry or microbiology. Despite efforts to provide educational feedback, no improvement was seen during the study period. Because of the dearth of data from other parts of the world it is not known for certain whether this study has merely pinpointed a local problem or if the same trend applies elsewhere.

Keywords: synovial fluid; joint fluid; quality control; crystals     

Changes of lymphocyte subsets in peripheral blood before and after operation of patients with advanced ovarian carcinoma

Summary Comparison was made between lymphocyte subsets in peripheral blood from patients with benign ovarian tumor and those with advanced ovarian carcinoma. In addition, changes of lymphocyte subsets of patients with ovarian carcinoma before and after operation were also examined. The percentage and absolute number of CD3^–/HLA-DR⁺ (B cells) in peripheral blood from patients with advanced ovarian carcinoma were significantly lower than values from patients with benign ovarian tumor, whereas both percentage and absolute number of CD3^–/HLA-DR^– (null cells) cells in patients with advanced ovarian carcinoma were significantly higher. Although there was no significant difference in natural killer (NK) cell subsets (CD57⁺CD16^– and CD57⁺ CD16⁺ cells) between patients with benign ovarian tumor and ovarian carcinoma, the percentage and absolute number of CD57^–/CD16⁺ (highly differentiated NK cells) cells in patients with ovarian carcinoma were significantly higher than those in patients with benign ovarian tumor. Both the absolute number and percentage of CD3⁺/HLA-DR⁺ (activated T cells) cells in ovarian cancer patients with minimal residual tumors after operation were significantly increased, compared to the levels before operation, while the values in the patients with large residual tumors were significantly decreased. In addition, the percentage and absolute number of CD3^–/HLA-DR^– (null cells) cells in the patients with minimal residual tumors were significantly decreased after operation, while values in the patients with large residual tumors remained unchanged before and after operation. The patients with minimal residual tumors after operation were characterized by a significant increase in the percentage of CD57^–CD16⁺ (highly differentiated NK cells) cells. On the other hand, in the patients with large residual tumors no change of the NK cell subsets was observed before and after operation.Abbreviation NK natural killer - FITC fluorescein isothiocyamate - PE phycoerythrin     

Impaired suppression of synovial fluid CD4+CD25− T cells from patients with juvenile idiopathic arthritis by CD4+CD25+ Treg cells

Objective

Natural CD4+CD25+FoxP3+ Treg cells play a crucial role in maintaining immune homeostasis and controlling autoimmunity. In patients with juvenile idiopathic arthritis (JIA), inflammation occurs despite the increased total numbers of Treg cells in the synovial fluid (SF) compared to the peripheral blood (PB). This study was undertaken to investigate the phenotype of CD4+ T cells in PB and SF from JIA patients, the function of synovial Treg cells, and the sensitivity of PB and SF CD4+CD25− effector T cells to the immunoregulatory properties of Treg cells, and to study the suppression of cytokine secretion from SF effector T cells by Treg cells.

Methods

The phenotypes of effector T cells and Treg cells of PB and SF from JIA patients and healthy donors were determined by flow cytometry. The functionality of isolated Treg cells and effector T cells was quantified in ³H‐thymidine proliferation assays. Cytokine levels were analyzed using Bio‐Plex Pro assay.

Results

Compared to PB, SF showed significantly elevated numbers of activated and differentiated CD4+CD45RO+ T cells. Sensitivity of SF effector T cells to the suppressive effects of Treg cells from both PB and SF was impaired, correlating inversely with the expression of CD69 and HLA–DR. However, SF effector T cell cytokine secretion was partly suppressed by SF Treg cells.

Conclusion

Our findings indicate that regulation is impaired in the SF of patients with JIA, as shown by the resistance of effector T cells to immunoregulation by functional Treg cells. This resistance of the SF effector T cells might be due to their activated phenotype.