Change in CD3 positive T-cell expression in psoriatic arthritis synovium correlates with change in DAS28 and magnetic resonance imaging synovitis scores following initiation of biologic therapy - a single centre, open-label study

Introduction

With the development of increasing numbers of potential therapeutic agents in inflammatory disease comes the need for effective biomarkers to help screen for drug efficacy and optimal dosing regimens early in the clinical trial process. This need has been recognized by the Outcome Measures in Rheumatology Clinical Trials (OMERACT) group, which has established guidelines for biomarker validation. To seek a candidate synovial biomarker of treatment response in psoriatic arthritis (PsA), we determined whether changes in immunohistochemical markers of synovial inflammation correlate with changes in disease activity scores assessing 28 joints (ΔDAS28) or magnetic resonance imaging synovitis scores (ΔMRI) in patients with PsA treated with a biologic agent.

Methods

Twenty-five consecutive patients with PsA underwent arthroscopic synovial biopsies and MRI scans of an inflamed knee joint at baseline and 12 weeks after starting treatment with either anakinra (first 10 patients) or etanercept (subsequent 15 patients) in two sequential studies of identical design. DAS28 scores were measured at both time points. Immunohistochemical staining for CD3, CD68 and Factor VIII (FVIII) was performed on synovial samples and scored by digital image analysis (DIA). MRI scans performed at baseline and at 12 weeks were scored for synovitis semi-quantitatively. The ΔDAS28 of the European League Against Rheumatism good response definition (>1.2) was chosen to divide patients into responder and non-responder groups. Differences between groups (Mann Whitney U test) and correlations between ΔDAS28 with change in immunohistochemical and MRI synovitis scores (Spearman's rho test) were calculated.

Results

Paired synovial samples and MRI scans were available for 21 patients (8 anakinra, 13 etanercept) and 23 patients (8 anakinra, 15 etanercept) respectively. Change in CD3 (ΔCD3) and CD68 expression in the synovial sublining layer (ΔCD68sl) was significantly greater in the disease responders compared to non-responders following treatment (P = 0.005 and 0.013 respectively). ΔCD3, but not ΔCD68 or ΔFVIII, correlated with both ΔDAS28 (r = 0.49, P = 0.025) and ΔMRI (r = 0.58, P = 0.009).

Conclusions

The correlation of ΔCD3 with ΔDAS28 and ΔMRI following biologic treatment in this cohort contributes to the validation of ΔCD3 as a synovial biomarker of disease response in PsA, and supports the further evaluation of ΔCD3 for predictive properties of future clinical outcomes.     

Arteriolo-venular anastomoses in the synovial membrane of the knee joint

The arteriolo-venular anastomoses (AVA) in the synovial membrane of the knee joint of fetuses (40), corpses of persons at various age (120) and dogs (30) have been studied by means of the impregnation method after V. V. Kupriyanov. In the synovial membrane shunts and semishunts are revealed. The AVA localize in composition of the deep vascular network of the synovial membrane. They are dynamic structures. The occurrence of their disclosure and their structure depend on the age factor.     

mu-Opioid receptor mRNA expression and immunohistochemical localization in the rat temporomandibular joint

This study was undertaken to examine the presence and distribution of the mu-opioid receptor (MOR) in the non-inflamed rat temporomandibular joint (TMJ) using non-radiographic in situ hybridization at the mRNA level and immunohistochemistry at the protein level. MOR mRNA and MOR-like immunoreactivity (MOR-LI) were found around the small blood vessels in the anterior part of the synovial membrane. The number of MOR mRNA signals in the anterior synovial membrane was significantly higher than that in the posterior part. Morphologically, MOR mRNA and MOR-LI were localized in amorphous materials considered to be nervous tissue, as well as some cell types considered to be macrophages, mast cells and endothelial cells. The present study showed the distribution of MOR in the rat TMJ synovial membrane and suggests that the opiate system plays an important role in endogenous analgesia in the TMJ.     

The specific expression of tenascin in the synovial membrane of the temporomandibular joint with internal derangement: An immunohistochemical study

 The expression of tenascin (TN) in the temporomandibular joint (TMJ) disc and synovial membrane was examined in 18 human TMJ samples from patients with internal derangement of the TMJ and ten control specimens by an immunohistological technique using paraffin-embedded tissue and specific anti-human TN monoclonal antibody (RCB-1). The expression of TN was observed in all 28 samples, but it was limited to the walls of blood vessels, the perineurium, and the surface of the TMJ disc. The expression of TN was diffuse in the stroma of mildly hypertrophic synovial membranes and focal in the surface of severely hypertrophic synovial membranes. The clinical symptoms of internal derangement of the TMJ are thought to be related to the degree of synovitis. The present study demonstrates that TN is expressed specifically in the portion of the TMJ synovial membrane affected with internal derangement. Accepted: 17 December 1996     

Evidence of reactive oxygen species generation in synovial fluid from patients with temporomandibular disease by electron spin resonance spectroscopy

Abstract

Reactive oxygen species (ROS) have been implicated in the pathogenesis of temporomandibular disorders. In the present study, we provide the first evidence of ROS generation in the synovial fluid from human temporomandibular disorder patients, as shown by electron spin resonance (ESR) and spin trapping. Three distinct ESR spectra of DMPO spin adducts were observed in the synovial fluid. They corresponded to three free radical species: hydroxyl radical (HO^?), hydrogen radical (H^?), and carbon-center radical (R^?). Among them, the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)-OH spectrum was the most prominent, suggesting that HO^? was dominantly generated in the synovial fluid from temporomandibular disorder patients. Desferrioxamine (DFO), an iron chelator, strongly depressed the DMPO-OH signal intensity in the synovial fluid from patients with temporomandibular disorders. We successfully demonstrated ROS-induced oxidative stress in the synovial fluid from temporomandibular disorder patients. ROS generation in the temporomandibular joint could lead to exacerbation of inflammation and activation of cartilage matrix degrading enzymes that proceed to degenerative change of the temporomandibular joint. Thus, iron-dependent generation of HO ^? might have a crucial role in the pathogenesis of temporomandibular disorders.     

Evidence of reactive oxygen species generation in synovial fluid from patients with temporomandibular disease by electron spin resonance spectroscopy

Reactive oxygen species (ROS) have been implicated in the pathogenesis of temporomandibular disorders. In the present study, we provide the first evidence of ROS generation in the synovial fluid from human temporomandibular disorder patients, as shown by electron spin resonance (ESR) and spin trapping. Three distinct ESR spectra of DMPO spin adducts were observed in the synovial fluid. They corresponded to three free radical species: hydroxyl radical (HO(*)), hydrogen radical (H(*)), and carbon-center radical (R(*)). Among them, the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)-OH spectrum was the most prominent, suggesting that HO(*) was dominantly generated in the synovial fluid from temporomandibular disorder patients. Desferrioxamine (DFO), an iron chelator, strongly depressed the DMPO-OH signal intensity in the synovial fluid from patients with temporomandibular disorders. We successfully demonstrated ROS-induced oxidative stress in the synovial fluid from temporomandibular disorder patients. ROS generation in the temporomandibular joint could lead to exacerbation of inflammation and activation of cartilage matrix degrading enzymes that proceed to degenerative change of the temporomandibular joint. Thus, iron-dependent generation of HO( *) might have a crucial role in the pathogenesis of temporomandibular disorders.     

Immunohistological assessment of the synovial tissue in small joints in rheumatoid arthritis: validation of a minimally invasive ultrasound-guided synovial biopsy procedure

The aim of the present study was to perform an immunohistological assessment of the synovial tissue from involved small joints in rheumatoid arthritis (RA) and to explore the reliability of a mini-invasive ultrasound (US)-guided technique of small joint synovial biopsy for the histopathological assessment. Synovial tissue collected during arthrotomic surgery of small joints in nine patients served as the gold standard for the validation of the histological assessment. Small hand-joint synovial biopsies from an additional nine patients with erosive RA were obtained by a mini-invasive US-guided procedure, performed percutaneously by the portal and rigid forceps technique. Using digital image analysis, the area fractions of synovial macrophages (CD68 cells), T cells (CD3 cells) and B cells (CD20 cells) were measured in all high-power fields of every sample at different cutting levels. The representative sample was defined as the minimal number of high-power fields whose mean area fraction would reflect the overall mean area fraction within a percentage mean difference of 10%. For each patient, a range of three to five large samples for surgical biopsies and a range of 8–12 samples for US-guided biopsies were collected and analysed. In arthrotomic samples, the analysis of a randomly selected tissue area of 2.5 mm² was representative of the overall value for CD68, CD3 and CD20 cells. US-guided samples allowed histological evaluation in 100% of cases, with a mean valid area of 18.56 mm² (range 7.29–38.28 mm²). The analysis of a cumulative area of 2.5 mm² from eight randomly selected sections (from different samples or from different cutting levels) allowed to reduce the percentage mean difference to less than 10% for CD68, CD3 and CD20 cells. In conclusion, US-guided synovial biopsy represents a reliable tool for the assessment of the histopathological features of RA patients with a mini-invasive approach.     

Upregulation of tumor necrosis factor receptor-associated factor 6 correlated with synovitis severity in rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction and disability. Focal bone erosion is due to excess bone resorption of osteoclasts. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is one of the critical mediators both in inflammatory signal pathway and differentiation and resorption activity of osteoclasts. Here we aimed to investigate TRAF6 expression in RA synovium and its correlation with histological synovitis severity and radiological joint destruction in RA.

Methods

Synovitis score was determined in needle biopsied synovium from 44 patients with active RA. Synovium from nine patients with osteoarthritis (OA) and seven with orthopedic arthropathies (Orth.A) were enrolled as "less inflamed" disease controls. Serial sections were stained immunohistochemically for TRAF6 as well as CD68 (macrophage), CD3 (T cell), CD20 (B cell), CD38 (plasmocyte), CD79a (B lineage cells from pre-B cell to plasmocyte stage), and CD34 (endothelial cell). Double immunofluorescence staining of TRAF6 and CD68 were tested. Densities of positive staining cells were determined and correlated with histological disease activity (synovitis score) and radiographic joint destruction (Sharp score).

Results

TRAF6 expression was found in the intimal and subintimal area of RA synovium, with intense staining found in the endochylema and nucleus of intimal synoviocytes and subintimal inflammatory cells. Double immunofluorescence staining showed TRAF6 was expressed in most of the intimal cells and obviously expressed in CD68+ cells and some other CD68- cells in subintimal area. Synovial TRAF6 was significantly over-expressed in the RA group compared with the OA and Orth.A group (2.53 ± 0.94 vs. 0.72 ± 0.44 and 0.71 ± 0.49, P < 0.0001). Synovial TRAF6 expression in RA correlated significantly with synovitis score (r = 0.412, P = 0.006), as well as the inflammatory cell infiltration (r = 0.367, P = 0.014). Significant correlation was detected between synovial TRAF6 expression and intimal CD68+ cells, as well as the cell density of subintimal CD68+ cells, CD3+ cells, CD20+ cells, CD38+ cells, and CD79a+ cells (all P < 0.05).

Conclusions

Elevated synovial TRAF6 expression correlated with synovitis severity and CD68+ cell density in RA. It is, therefore, hypothesized that synovial TRAF6 is involved in the pathogenesis of synovial inflammation and osteoclast differentiation in RA.     

关节灌洗术联合透明质酸钠注射治疗颞下颌关节骨关节炎的疗效观察

目的:评价关节腔灌洗联合透明质酸钠注射治疗颞下颌关节骨关节炎(TMJOA)的疗效及安全性。方法:选取我院2014年5月-2015年5月收治颞下颌关节骨关节炎患者68例作为研究对象,根据入院时间先后顺序按照随机数字表法随机分为实验组和对照组各34例。所有患者在颞颌关节区域局麻下建立关节上腔的双通道灌洗系统,实验组用生理盐水反复冲洗关节腔后注射透明质酸钠,对照组只进行关节腔灌洗术,术后随访对比两组治疗前、治疗后4周、6个月时患者非辅助最大开口度、侧向运动幅度、咀嚼时疼痛感;同时采用酶联免疫吸附法(ELISA)测定两组治疗前、治疗后4周血清中白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)水平并进行比较。结果:实验组患者治疗后4周、治疗后6个月时颞下颌关节最大张口度和侧向活动距离明显增大,而咀嚼时疼痛感明显减轻,且优于同期对照组,差异具有统计学意义(P0.05);实验组患者治疗后4周时血清IL-6、TNF-α水平较术前及同时期对照组均明显降低,差异具有统计学意义(P0.05)。结论:关节灌洗术联合透明质酸钠注射是治疗颞下颌关节骨关节炎的简单、安全有效治疗方法,治疗效果明显优于单纯关节腔灌洗,值得临床推广应用。     

Relationship between patient-reported disease severity in osteoarthritis and self-reported pain, function and work productivity

Introduction

The purpose of this study was theevaluation of synovial effusion (SE), synovial fluid (SF) and synovial tissue (ST) biomarkers in relation to disease activity indexes to assess the response to intraarticular (IA) tumor necrosis factor (TNF)-α blockers in psoriatic arthritis (PsA).

Methods

Systemic and local disease activity indexes (disease activity score (DAS); the Ritchie articular index (mRAI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP); Thompson articular (THOMP) and joint articular (KJAI)-Index ) and ST samples were assessed at baseline, throughout treatment, and during the follow-up in 14 patients affected with PsA who underwent IA injections (0.5 ml to 12.5 mg) in the knee joint of etanercept (E) or placebo (P) once every two weeks for a 10-week period. Total SF white blood cell (WBC) counts (WBC/μl) and SF cytokine/chemokine (CK/CCK) levels were measured before IA-E at baseline, after IA-E, and as long as there were adequate amounts of SF for knee aspiration (post). Characterization of synovial mononuclear cell infiltration and synovial vessels was carried out in 8 out of 14 knees by staining serial sections of synovial tissue biopsies for CD45, CD3, CD68, CD31 and CD105.

Results

At baseline, CRP and/or ESR were significantly correlated with SF-CK (interleukin- (IL-)1β, IL-1Ra, IL-6, IL-8) and CCK (CCL3). Post-IA injections, there was a decrease in SE in the knees in which aspiration following IA-E injection was possible as well as a significant reduction in SF WBC/μl and in SF-CK (IL-1β, IL-1Ra, IL-6 and IL-22). Pre- and post-IA-E injections, there were significant correlations between ST markers and SF-CK (IL-1β with CD45; IL-1β and IL-6 with CD31) and between SF-CCK (CCL4 and CCL3 with CD3). At the end of the study, there was a significant reduction in disease activity indexes (CRP, DAS, RAI, THOMP, KJAI) as well as in the ST markers (CD45; CD3).

Conclusions

Synovial effusion regression is a reliable indicator of the response to IA TNF-α blockers in PsA patients as it is confirmed by the correlation between SF biomarkers to disease activity and synovial tissue inflammation.     

Development of the temporomandibular joint in miniature pig embryos

The temporomandibular joint (TMJ) is a synovial joint involved in sliding and hinge movements of lower jaw in mammals. Studies on TMJ development in embryos have been mainly performed using rodents. However, the TMJ structure in rodents differs in several aspects from that in humans. There are few studies on the embryonic development of TMJ in large mammals. In the present study, we investigated the embryonic developmental characteristics of the TMJ in pigs histologically. Embryonic day 35 (E35), E45, E55, E75, E90, and postnatal day 1(P1) embryos/fetuses from the pigs were used for the study. The results showed condensation of mesenchymal cells on E35. The inferior articular cavity was formed on E45, together with a narrow crack in the superior articular cavity region. The superior and inferior articular cavities and articular disc of the TMJ were completely formed on E55. On E75, the condyle showed an obvious conical shape and the superior and inferior joint cavities were enlarged. Furthermore, the mandibular ramus and mandibular body under the neck of the condyle were ossified from E75 to P1 day. The chondrocyte layer of the condyle was significantly thinner from E75 to P1. It is speculated that the spatiotemporal development of the TMJ in miniature pig embryos is similar to that in humans. Embryonic development of the pig TMJ is an important bridge for translating the results of rodent research to medical applications.     

Stage-specific localization of the small heat shock protein Hsp27 during oogenesis inDrosophila melanogaster

The developmental and heat shock-induced expression of the small heat shock protein Hsp27 was investigated by confocal microscopy of whole-mount immunostained preparations of ovarioles during oogenesis inDrosophila melanogaster. In unstressed flies, Hsp27 was mainly associated with germline nurse cells throughout egg development. A small group of somatic follicle cells also expressed Hsp27 specifically at stages 8 to 10 of oogenesis. Interestingly, this Hsp showed a different intracellular localization depending on the stages of egg chamber development. Thus Hsp27 was localized in the nucleus of nurse cells during the first stages of oogenesis (from germarium to stage 6) whereas it showed a perinuclear and cytoplasmic localization from stage 8. After a heat shock, Hsp27 accumulated in somatic follicle cells surrounding the egg chamber whereas the expression of this small Hsp did not seem to be enhanced in nurse cells. The stage-dependent pattern of intracellular localization of Hsp27 observed in nurse cells of unstressed flies was also observed following heat shock. At late stages of oogenesis, Hsp27 also showed a perinuclear distribution in follicle and nurse cells after heat stress. These observations suggest that different factors may modulate the expression and intracellular distribution of Hsp27. This modulation may be associated with the specific activities occurring in each particular cell type throughout oogenesis during both normal development and under heat shock conditions. Edited by: E.R. Schmidt     

The role of the cysteine residue in the chaperone and anti‐apoptotic functions of human Hsp27

The small heat shock protein Hsp27 is a molecular chaperone and an anti‐apoptotic protein. Human Hsp27 has one cysteine residue at position 137. We investigated the role of this cysteine residue in the chaperone and anti‐apoptotic functions of Hsp27 by mutating the cysteine residue to an alanine (Hsp27_C137A) and comparing it to wild‐type protein (Hsp27_WT). Both proteins were multi‐subunit oligomers, but subunits of Hsp27_WT were disulfide‐linked unlike those of Hsp27_C137A, which were monomeric. Hsp27_C137A was indistinguishable from Hsp27_WT with regard to its secondary structure, surface hydrophobicity, oligomeric size and chaperone function. S‐thiolation and reductive methylation of the cysteine residue had no apparent effect on the chaperone function of Hsp27_WT. The anti‐apoptotic function of Hsp27_C137A and Hsp27_WT was studied by overexpressing them in CHO cells. No difference in the caspase‐3 or ‐9 activity was observed in staurosporine‐treated cells. The rate of apoptosis between Hsp27_C137A and Hsp27_WT overexpressing cells was similar whether the cells were treated with staurosporine or etoposide. However, the mutant protein was less protective relative to the wild‐type protein in preventing caspase‐3 and caspase‐9 activation and apoptosis induced by 1 mM H₂O₂ in CHO and HeLa cells. These data demonstrate that in human Hsp27, disulfide formation by the lone cysteine does not affect its chaperone function and anti‐apoptotic function against chemical toxicants. However, oxidation of the lone cysteine in Hsp27 might at least partially affect the anti‐apoptotic function against oxidative stress. J. Cell. Biochem. 110: 408–419, 2010. © 2010 Wiley‐Liss, Inc.     

Apolipoprotein-A1 as a Damage-Associated Molecular Patterns Protein in Osteoarthritis: Ex Vivo and In Vitro Pro-Inflammatory Properties

Osteoarthritis (OA) is associated with a local inflammatory process. Dyslipidemia is known to be an underlying cause for the development of OA. Therefore, lipid and inflammatory levels were quantified ex vivo in blood and synovial fluid of OA patients (n=29) and compared to those of rheumatoid arthritis (RA) patients (n=27) or healthy volunteers (HV) (n=35). The role of apolipoprotein A-I (ApoA1) was investigated in vitro on inflammatory parameters using human joint cells isolated from cartilage and synovial membrane obtained from OA patients after joint replacement. Cells were stimulated with ApoA1 in the presence or not of serum amyloid A (SAA) protein and/or lipoproteins (LDL and HDL) at physiological concentration observed in OA synovial fluid. In our ex vivo study, ApoA1, LDL-C and total cholesterol levels were strongly correlated to each other inside the OA joint cavity whereas same levels were not or weakly correlated to their corresponding serum levels. In OA synovial fluid, ApoA1 was not as strongly correlated to HDL as observed in OA serum or in RA synovial fluid, suggesting a dissociative level between ApoA1 and HDL in OA synovial fluid. In vitro, ApoA1 induced IL-6, MMP-1 and MMP-3 expression by primary chondrocytes and fibroblast-like synoviocytes through TLR4 receptor. HDL and LDL attenuated joint inflammatory response induced by ApoA1 and SAA in a ratio dependent manner. In conclusion, a dysregulated lipidic profile in the synovial fluid of OA patients was observed and was correlated with inflammatory parameters in the OA joint cavity. Pro-inflammatory properties of ApoA1 were confirmed in vitro.     

Lubricin Protects the Temporomandibular Joint Surfaces from Degeneration

The temporomandibular joint (TMJ) is a specialized synovial joint essential for the mobility and function of the mammalian jaw. The TMJ is composed of the mandibular condyle, the glenoid fossa of the temporal bone, and a fibrocartilagenous disc interposed between these bones. A fibrous capsule, lined on the luminal surface by the synovial membrane, links these bones and retains synovial fluid within the cavity. The major component of synovial fluid is lubricin, a glycoprotein encoded by the gene proteoglycan 4 (Prg4), which is synthesized by chondrocytes at the surface of the articular cartilage and by synovial lining cells. We previously showed that in the knee joint, Prg4 is crucial for maintenance of cartilage surfaces and for regulating proliferation of the intimal cells in the synovium. Consequently, the objective of this study was to determine the role of lubricin in the maintenance of the TMJ. We found that mice lacking lubricin have a normal TMJ at birth, but develop degeneration resembling TMJ osteoarthritis by 2 months, increasing in severity over time. Disease progression in Prg4 ^−/− mice results in synovial hyperplasia, deterioration of cartilage in the condyle, disc and fossa with an increase in chondrocyte number and their redistribution in clusters with loss of superficial zone chondrocytes. All articular surfaces of the joint had a prominent layer of protein deposition. Compared to the knee joint, the osteoarthritis-like phenotype was more severe and manifested earlier in the TMJ. Taken together, the lack of lubricin in the TMJ causes osteoarthritis-like degeneration that affects the articular cartilage as well as the integrity of multiple joint tissues. Our results provide the first molecular evidence of the role of lubricin in the TMJ and suggest that Prg4 ^−/− mice might provide a valuable new animal model for the study of the early events of TMJ osteoarthritis.     

Synovial effusion and synovial fluid biomarkers in psoriatic arthritis to assess intraarticular tumor necrosis factor-α blockade in the knee joint

Introduction

The purpose of this study was theevaluation of synovial effusion (SE), synovial fluid (SF) and synovial tissue (ST) biomarkers in relation to disease activity indexes to assess the response to intraarticular (IA) tumor necrosis factor (TNF)-α blockers in psoriatic arthritis (PsA).

Methods

Systemic and local disease activity indexes (disease activity score (DAS); the Ritchie articular index (mRAI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP); Thompson articular (THOMP) and joint articular (KJAI)-Index ) and ST samples were assessed at baseline, throughout treatment, and during the follow-up in 14 patients affected with PsA who underwent IA injections (0.5 ml to 12.5 mg) in the knee joint of etanercept (E) or placebo (P) once every two weeks for a 10-week period. Total SF white blood cell (WBC) counts (WBC/μl) and SF cytokine/chemokine (CK/CCK) levels were measured before IA-E at baseline, after IA-E, and as long as there were adequate amounts of SF for knee aspiration (post). Characterization of synovial mononuclear cell infiltration and synovial vessels was carried out in 8 out of 14 knees by staining serial sections of synovial tissue biopsies for CD45, CD3, CD68, CD31 and CD105.

Results

At baseline, CRP and/or ESR were significantly correlated with SF-CK (interleukin- (IL-)1β, IL-1Ra, IL-6, IL-8) and CCK (CCL3). Post-IA injections, there was a decrease in SE in the knees in which aspiration following IA-E injection was possible as well as a significant reduction in SF WBC/μl and in SF-CK (IL-1β, IL-1Ra, IL-6 and IL-22). Pre- and post-IA-E injections, there were significant correlations between ST markers and SF-CK (IL-1β with CD45; IL-1β and IL-6 with CD31) and between SF-CCK (CCL4 and CCL3 with CD3). At the end of the study, there was a significant reduction in disease activity indexes (CRP, DAS, RAI, THOMP, KJAI) as well as in the ST markers (CD45; CD3).

Conclusions

Synovial effusion regression is a reliable indicator of the response to IA TNF-α blockers in PsA patients as it is confirmed by the correlation between SF biomarkers to disease activity and synovial tissue inflammation.     

Ultrastructural characteristics of the human synoviocytes

The purpose of this study was to identify, by the scanning electron microscopy, the behaviour of the different cell types in the normal human synovial intima, in order to obtain information useful for interpreting pathological changes in the synovium. Our observations revealed that, in numerous areas of the synovial membrane (adipose or fibrous type), the synoviocytes were dispersed and the intercellular matrix, covered only by the cytoplasmic processes of cells deeply located, was in direct contact with the joint cavity. In the areolar type of the synovium the synoviocytes were more numerous; they tended to concentrate to give the appearance of a continuous tissue; but between the cells very large intercellular spaces were usually present. In this latter membrane type we identified the two main cellular types of the synoviocytes: A and B. B-synoviocytes were the predominant cell type of the synovium. These cells were characterized by long cytoplasmic processes, perpendicularly directed towards the joint cavity. Both the cellular body and the cytoplasmic processes were covered by small blebs and vesicles of various size. The A-synoviocytes were a small minority, rarely dispersed between the B-synoviocytes. They were characterized by numerous membrane infoldings which delimited intracellular canaliculi of various depth. Our ultrastructural observations demonstrated that, in normal conditions, the B-synoviocyte must be considered as a constitutive element which characterized the synovial intima, responsible for the specific structure of the interstitial tissue and for the regulation of the composition of the synovial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skewed distribution of proinflammatory CD4+CD28null T cells in rheumatoid arthritis

Expanded populations of CD4+ T cells lacking the co-stimulatory molecule CD28 (CD4+CD28null T cells) have been reported in several inflammatory disorders. In rheumatoid arthritis, increased frequencies of CD4+CD28null T cells in peripheral blood have previously been associated with extra-articular manifestations and human cytomegalovirus (HCMV) infection, but their presence in and contribution to joint manifestations is not clear. In the present article we investigated the distribution of CD4+CD28null T cells in the synovial membrane, synovial fluid and peripheral blood of RA patients, and analysed the association with erosive disease and anti-citrullinated protein antibodies. CD4+CD28null T cells were infrequent in the synovial membrane and synovial fluid, despite significant frequencies in the circulation. Strikingly, the dominant TCR-Vbeta subsets of CD4+CD28null T cells in peripheral blood were often absent in synovial fluid. CD4+CD28null T cells in blood and synovial fluid showed specificity for HCMV antigens, and their presence was clearly associated with HCMV seropositivity but not with anti-citrullinated protein antibodies in the serum or synovial fluid, nor with erosive disease. Together these data imply a primary role for CD4+CD28null T cells in manifestations elsewhere than in the joints of patients with HCMV-seropositive rheumatoid arthritis.     

Synovial expression of IL-15 in rheumatoid arthritis is not influenced by blockade of tumour necrosis factor

Blockade of tumour necrosis factor (TNF) is an effective treatment in rheumatoid arthritis (RA), but both non-responders and partial responders are quite frequent. This suggests that other pro-inflammatory cytokines may be of importance in the pathogenesis of RA and as possible targets for therapy. In this study we investigated the effect of TNF blockade (infliximab) on the synovial expression of IL-15 in RA in relation to different cell types and expression of other cytokines, to elucidate whether or not IL-15 is a possible target for therapy, independently of TNF blockade. Two arthroscopies with multiple biopsies were performed on nine patients with RA and knee-joint synovitis before and after three infusions of infliximab (3 mg/kg). Synovial biopsies were analysed with immunohistochemistry for expression of IL-15, TNF, IL-1α, IL-1ß and IFN-γ, and for the cell surface markers CD3, CD68 and CD163. Stained synovial biopsy sections were evaluated by computerized image analysis. IL-15 expression was detected in all synovial biopsies taken at baseline. After infliximab therapy, the expression of IL-15 was increased in four patients and reduced in five. Synovial expression of IL-15 was not correlated with any CD marker or with the presence of any other cytokine. Synovial cellularity was decreased after 8 to 10 weeks of treatment with a significant reduction of the CD68-positive synovial cells, whereas no significant change was seen in the number of CD3-positive T cells and CD163-expressing macrophages. The number of TNF-producing cells in the synovial tissue at baseline was correlated with a good response to therapy. Thus, in this study the synovial expression of IL-15 in RA was not consistently influenced by TNF blockade, being apparently independent of TNF expression in the synovium. Consequently, we propose that IL-15 should remain as a therapeutic target in RA, regardless of the response to TNF blockade.