Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients.

Complement receptors (CRs) play an integral role in innate immunity and also function to initiate and shape the adaptive immune response. Our earlier results showed that complement receptor type 1 (CR1, CD35) is a potent inhibitor of the B cell receptor- (BCR-) induced functions of human B lymphocytes. Here we show that this inhibition occurs already at the initial steps of B cell activation since ligation of CR1 reduces the BCR-induced phosphorylation of key signaling molecules such as Syk and mitogen activated protein kinases (MAPKs). Furthermore, our data give evidence that although B lymphocytes of active systemic lupus erythematosus (SLE) patients express lower level of CR1, the inhibitory capacity of this complement receptor is still maintained and its ligand-induced clustering results in significant inhibition of the main B cell functions, similar to that found in the case of healthy individuals. Since we have found that reduced CR1 expression of SLE patients does not affect the inhibitory capacity of the receptor, our results further support the therapeutical potential of CD35 targeting the decrease of B cell activation and autoantibody production in autoimmune patients.

Peripheral CD4+ cell prevalence and pleuropulmonary manifestations in systemic lupus erythematosus patients.

INTRODUCTION: Systemic lupus erythematosus (SLE) is an autoimmune disease involving several organs, including the lungs. Previous results confirmed changes of peripheral T cell subsets in lupus patients; however no data are available about their possible relationship with pulmonary involvement. OBJECTIVE: To determine pulmonary manifestations and potential relationship in changes of peripheral CD4+ T cell subsets. METHODS: Patients with SLE (N = 28) were enrolled in complex pulmonary examination. Patients were divided into groups with pleuropulmonary manifestations (SLEpulm N = 13 age: 44.9 ± 3.3 years, female: male = 11:2) or without (SLEc N = 15 age: 27.2 ± 3.7 years, female: male = 12:3). Peripheral blood was taken for T helper (Th)1, Th2, Th17, CD4+CD25hi+ and regulatory T (Treg: CD4+CD25hi+ CD127-) cell analysis from SLE patients and healthy volunteers (controls, N = 40). RESULTS: SLEpulm patients were older, had more pulmonary symptoms and significantly decreased pO2 as compared to SLEc group. Ventilatory disorder was present in 92% of SLEpulm patients, with significantly decreased lung volumes, signs of airway involvement and decrease in DLco. Significant increase in Th1/Th2, while decrease in Th17/Treg ratios was present in all SLE compared to controls. In SLEpulm CD4+CD25hi+ subset without changes in Treg number was significantly increased as compared to SLEc and this subgroup of T cell showed significant positive correlation with dynamic lung function parameters and DLco (p < 0.05). CONCLUSION: In lupus patients pleuropulmonary manifestations are prevalent and lung function and blood gas measurements should be regularly performed in the daily clinical assessment. Significant increase of activated CD4+CD25hi+ T cells, but not Treg is associated with decreased lung function parameters in SLEpulm patients.

Complement receptor type 1 (CR1, CD35) is a potent inhibitor of B-cell functions in rheumatoid arthritis patients.

The involvement of B cells, complement activation and subsequent immune complex deposition has all been implicated in the pathogenesis of rheumatoid arthritis (RA). Although the reduced expression of complement receptor 1 (CR1, CD35) and 2 (CR2, CD21) on the B cells of RA patients has been known for a long time, their exact role in B-cell tolerance and autoimmunity is not yet fully understood. To get a deeper insight into the possible mechanisms, we studied the expression and function of CR1 and CR2 on various subsets of B cells of healthy donors and RA patients at various stages of the disease by FACS analysis, (3)H-thymidine incorporation and ELISA. We found that CD19(+)CD27(-) naive B cells up-regulate the expression of the inhibitory CR1 during differentiation to CD19(+)CD27(+) memory B cells both in healthy donors and in RA patients, whereas the expression of the activatory CR2 is down-regulated. This clearly demonstrates that the expression of these two antagonistic complement receptors is regulated differentially during the development of human B cells, a phenomenon which may influence the maintenance of peripheral B-cell tolerance. Our functional studies show that after clustering CR1 both by its natural ligand and To5 mAb, the inhibitory function of CD35 is maintained in RA patients, despite its significantly reduced expression compared with healthy individuals. Besides blocking B-cell receptor-induced proliferation, CR1 inhibits the differentiation of B cells to plasmablasts and their immunoglobulin production. Since the reduced expression of CR1 in RA patients does not affect its inhibitory function, this receptor might serve as a new target for therapeutical interventions.

Improved flow cytometric assessment reveals distinct microvesicle (cell-derived microparticle) signatures in joint diseases.

INTRODUCTION: Microvesicles (MVs), earlier referred to as microparticles, represent a major type of extracellular vesicles currently considered as novel biomarkers in various clinical settings such as autoimmune disorders. However, the analysis of MVs in body fluids has not been fully standardized yet, and there are numerous pitfalls that hinder the correct assessment of these structures. METHODS: In this study, we analyzed synovial fluid (SF) samples of patients with osteoarthritis (OA), rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). To assess factors that may confound MV detection in joint diseases, we used electron microscopy (EM), Nanoparticle Tracking Analysis (NTA) and mass spectrometry (MS). For flow cytometry, a method commonly used for phenotyping and enumeration of MVs, we combined recent advances in the field, and used a novel approach of differential detergent lysis for the exclusion of MV-mimicking non-vesicular signals. RESULTS: EM and NTA showed that substantial amounts of particles other than MVs were present in SF samples. Beyond known MV-associated proteins, MS analysis also revealed abundant plasma- and immune complex-related proteins in MV preparations. Applying improved flow cytometric analysis, we demonstrate for the first time that CD3(+) and CD8(+) T-cell derived SF MVs are highly elevated in patients with RA compared to OA patients (p=0.027 and p=0.009, respectively, after Bonferroni corrections). In JIA, we identified reduced numbers of B cell-derived MVs (p=0.009, after Bonferroni correction). CONCLUSIONS: Our results suggest that improved flow cytometric assessment of MVs facilitates the detection of previously unrecognized disease-associated vesicular signatures.

Devic's syndrome and SLE: challenges in diagnosis and therapeutic possibilities based on two overlapping cases.

Neuromyelitis optica (NMO, Devic's disease), an uncommon demyelinating neuro-immunological disease, can be associated with autoimmune diseases. In SLE associated forms anti-aquaporin-4 antibody positivity can help differentiating between SLE nerve system manifestation and NMO. In the literature rituximab, or immunoablative dose cyclophosphamide (CYC) was effective for the therapy resistant forms. Authors present 2 SLE overlapping NMO cases, one of them with SLE associated interstitial lung disease (ILD). In both cases neurological manifestations anticipated other SLE symptoms. Patients previously were treated with high dose corticosteroid therapy, plasmapheresis, and one of them with azathioprine, and the other one with oral CYC (which could not prevent flares). 0.5 g/m² body-surface monthly parenteral inductive CYC therapy was administered, in one patient followed by quarterly maintenance therapy. This patient completed her 18 month maintenance treatment and has been in neurological remission, but required steroid pulse and plasmapheresis for lung symptoms. The second patient had urogenital infection after the induction phase, followed by an exacerbation, requiring plasmapheresis and high dose parenteral corticosteroid treatment. After it he refused CYC therapy and has been taking azathioprine. He has no new symptoms, only residual ones. In our two patients conventional dose CYC therapy proved to be effective for NMO/SLE overlap, required only transient supportive therapy.

Detection and isolation of cell-derived microparticles are compromised by protein complexes resulting from shared biophysical parameters.

Numerous diseases, recently reported to associate with elevated microvesicle/microparticle (MP) counts, have also long been known to be characterized by accelerated immune complex (IC) formation. The goal of this study was to investigate the potential overlap between parameters of protein complexes (eg, ICs or avidin-biotin complexes) and MPs, which might perturb detection and/or isolation of MPs. In this work, after comprehensive characterization of MPs by electron microscopy, atomic force microscopy, dynamic light-scattering analysis, and flow cytometry, for the first time, we drive attention to the fact that protein complexes, especially insoluble ICs, overlap in biophysical properties (size, light scattering, and sedimentation) with MPs. This, in turn, affects MP quantification by flow cytometry and purification by differential centrifugation, especially in diseases in which IC formation is common, including not only autoimmune diseases, but also hematologic disorders, infections, and cancer. These data may necessitate reevaluation of certain published data on patient-derived MPs and contribute to correct the clinical laboratory assessment of the presence and biologic functions of MPs in health and disease.

Cost-of-illness of patients with systemic sclerosis in a tertiary care centre.

OBJECTIVE: The aim of our study was to assess the costs of SSc and to analyse cost drivers. METHODS: A cross-sectional survey of consecutive patients with SSc was performed in a rheumatology centre in Hungary. Clinical characteristics, the European Scleroderma Study Group activity index, disease severity scale (DSS), scleroderma HAQ (S-HAQ) and health care utilization were recorded. Cost calculation was performed and correlation with clinical variables was analysed. Results were compared with RA and PsA. RESULTS: Eighty patients were involved: 72 (90%) women, mean age (s.d.) 57.4 (9.6) years and disease duration of 6.2 (6.6) years and 25% of the cases had dcSSc. Mean total cost was 9619 (s.d. 6444) euros/patient/year with rate of indirect cost being 56%. Disability-related productivity loss (55.2%) and hospitalization (28.3%) were the highest among the cost items. Patients with dcSSc had significantly higher direct costs (P = 0.005) compared with the lcSSc subset. Disease activity showed significant correlation with total costs, DSS and S-HAQ with direct costs. SSc-related costs were higher than in matched RA and PsA cases. CONCLUSIONS: The cost-of-illness of SSc is high with a dominance of productivity loss related costs. Moreover, the disease activity is an important cost driver.

Disease burden of psoriatic arthritis compared to rheumatoid arthritis, Hungarian experiment.

The objectives of this study were to assess the costs of psoriatic arthritis (PsA) in Hungary and to identify key cost drivers among demographic and clinical variables and to compare cost-of-illness of PsA and rheumatoid arthritis (RA). Cross-sectional retrospective survey of 183 consecutive patients from eight rheumatology centres was conducted. Mean direct medical, direct non medical, indirect and total costs were 1,876, 794, 2,904 and 5,574 euros/patient/year, respectively. Total costs were in significant linear relationship with health assessment questionnaire score and psoriatic area severity index. Costs of RA were higher in all domains than of PsA. Our study was the first from the Eastern European region that provides cost-of-illness data on PsA. Our study revealed that functional status and severity of skin symptoms were the key cost drivers. The costs of PsA in Hungary were lower than in the high-income European countries.

Natural autoantibodies reactive with glycosaminoglycans in rheumatoid arthritis.

INTRODUCTION: Although natural autoantibodies make up the majority of circulating immunoglobulins and are also present in high numbers in therapeutically used intravenous immunoglobulin preparations, they have received little attention and their precise role remains largely unknown. An increasing awareness of the importance of posttranslational autoantigen modifications and glycobiology led us to explore carbohydrate-reactive natural autoantibodies in patients with rheumatoid arthritis. This study examined systematic antibodies reactive to glycosaminoglycans (GAGs), the carbohydrate components of proteoglycans that are released in large amounts from degrading cartilage. METHODS: To measure antibodies reactive to six different types of GAGs, a specialised ELISA was used in which the carbohydrates were covalently linked to the plastic surface through a 2 nm spacer. Sera from rheumatoid arthritis patients (n = 66), umbilical cord serum samples (n = 11) and adult controls (n = 54) were studied. In order to explore cross-reactivity with microbial antigens, bacterial peptidoglycans and fungal polysaccharides were used. Sera and synovial fluid samples were also tested using a GlycoChip carbohydrate array to characterise individual carbohydrate recognition patterns. We followed a multistep statistical screening strategy for screening GAG-reactive antibodies as predictive disease markers. RESULTS: While anti-GAG antibodies were absent in the umbilical cord sera, they were readily detectable in adult controls and were significantly elevated in patients with rheumatoid arthritis (p < 0.001). Anti-GAG antibodies showed significant cross-reactivity among different types of GAGs. They also reacted with bacterial peptidoglycans and fungal polysaccharides. Interestingly, anti-chondroitin sulphate C IgM antibody levels showed inverse correlation both with the Disease Activity Score (DAS) 28 scores and C-reactive protein (CRP) levels in rheumatoid arthritis. CONCLUSION: The highly abundant and cross-reactive, GAG-specific natural autoantibodies in serum may serve as novel disease-state markers in patients with rheumatoid arthritis.

[Impact of disease progression on health status, quality of life and costs in rheumatoid arthritis in Hungary]. / A betegségprogresszió hatása az egészségi állapotra, életminoségre és költségekre rheumatoid arthritisben Magyarországon.

UNLABELLED: Rheumatoid arthritis (RA) is a chronic, progressive polyarthritis leading to substantial disability. Standardised data on consequences of disease progression are needed for clinical assessments and also for cost-effectiveness models. AIM: To analyse the impact of disease progression on health status, disease specific quality of life and costs in Hungary. METHODS: A cross-sectional survey was performed between April and August, 2004, involving consecutive RA patients of 6 hospital based rheumatology outpatient centres. Self-completed questionnaires were used to assess functional (HAQ) and health status (EQ-5D), quality of life (RAQoL). Disease activity (DAS) and costs were also surveyed, statistical analysis was performed. RESULTS: 255 patients were involved [mean age 55.5 +/- 12.3 years; disease duration 9.0 +/- 9.3 years; HAQ 1.38 +/- 0.76; EQ-5D 0.46 +/- 0.33; RAQoL 16.2 +/- 8.1; DAS 5.09 +/- 1.42; costs 1,043,163 (+/- 844,750) HUF/patient/year, conversion 1 Euro = 250 HUF]. Correlation was significant between the parameters ( p < 0.01): EQ-5D index = 1.014 - 0.25 x HAQ-0.041 x DAS; HAQ = 0.314 + 0.065 x RAQoL. Analysis by disease severity levels (HAQ groups 0.5 difference) revealed that health status worsens (mean EQ-5D: 0.784; 0.576; 0.504; 0.367; 0.211; 0.022) and costs increase (mean 628,280; 888,187; 953,759; 1,291,218; 1,346,112; 1,371,674 HUF/patient/year) with disease progression. Minimally important worsening of functional ability (0.25 HAQ increase) corresponds to -0.0705 EQ-5D and +1.884 RAQoL change. Lower health status difference (EQ-5D -0.05725) was calculated in patients with lower disease activity (DAS < 5.1). CONCLUSIONS: Correlation between disease progression, health status, quality of life and costs does not differ significantly from international results. The amount of costs is much lower in all disease severity levels than in developed European countries. Our study serves baseline data for health economic analysis in RA in Hungary.

Synovial fluid exoglycosidases are predictors of rheumatoid arthritis and are effective in cartilage glycosaminoglycan depletion.

OBJECTIVE: To analyze enzymes involved in joint damage by simultaneous investigation of glycosidases and matrix metalloproteinases (MMPs) in patients with various joint diseases. METHODS: Activities of glycosidases (beta-D-glucuronidase, beta-D-N-acetyl-glucosaminidase, beta-D-N-acetyl-galactosaminidase, beta-D-galactosidase, and alpha-D-mannosidase) were tested at an acidic pH as well as at the original pH of the synovial fluid (SF) samples in parallel with activities of MMP-1 and MMP-9. RESULTS: Patients with rheumatoid arthritis (RA) were characterized by significantly elevated activities of beta-D-glucuronidase and beta-D-N-acetyl-glucosaminidase in SF compared with patients with osteoarthritis, seronegative spondylarthritis, or acute sports injury. To select the best predictor for distinguishing among patient groups, a stepwise logistic regression analysis was performed; the strongest association was found to be between RA and beta-D-glucuronidase/beta-D-N-acetyl-glucosaminidase activities (measured at the pH of the SF). Further, a significant correlation was observed between the activity of SF beta-D-N-acetyl-glucosaminidase and the level of rheumatoid factor. In vitro digestion of human hyaline cartilage samples revealed that the dominant glycosidases, alone or in combination with MMPs, proved to be effective in depleting glycosaminoglycans (GAGs) from cartilage. CONCLUSION: These results suggest that exoglycosidases, which are present in the SF of RA patients, may contribute to the depletion of GAGs from cartilage and thereby facilitate the invasion of synovial cells and their attachment to cartilage in RA.

A synthetic corticosteroid, dexamethasone regulates generation of soluble form of interleukin-6 receptor of human lymphocytes, in vitro.

In contrast to most of the soluble cytokine receptor antagonists properties, the soluble IL-6 receptor (sIL-6R) occurring in various body fluids of healthy persons and patients with various diseases is an agonist. The enhancing effect is due to its ability to form complex with IL-6 and to bind to gp130 making constitutively IL-6 receptor negative cells responsive for IL-6. The generation as well as the functional role of soluble IL-6 receptor is poorly understood. Earlier, we found that the sIL-6R levels in sera of patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) were higher than those of the control group measured by ELISA sandwich technology. In the present study we detected different levels of sIL-6R in the supernatants of lymphocyte cultures of healthy persons and patients with RA as well as SLE. Moreover, we found, that in vitro dexamethasone treatment stimulated generation of sIL-6R in both healthy persons and in active SLE, while it strongly suppressed production of sIL-6R in both RA groups. At mRNA level, we found that in SLE both the IL-6R mRNA encoding the membrane spanning and alternatively spliced (soluble) variants increased. Surprisingly, the strong decrease of sIL6R protein in RA was not found at mRNA level.

Soluble interleukin-6 receptor enhanced by oncostatin M induces major changes in gene expression profile of human hepatoma cells.

Interleukin-6 (IL-6) binds to a receptor complex consisting of an 80 kDa binding unit (IL-6R) and gp130 responsible for signal transduction. Due to alternative splicing and/or proteolytic digestion IL-6R occurs in soluble form (sIL-6R), as well. Soluble IL-6R is able to bind to gp130 expressing on nucleated cells, thus sIL-6R makes most cells responsive to IL-6. In this study we found that oncostatin M (OSM), an other gp130 dependent cytokine with proliferation inhibitory potential, increases the expression of both membrane-bound IL-6R and sIL-6R generated by alternative splicing in hepatic and mammary carcinoma cell lines. Furthermore, we studied the functional relevance of the presence and binding of soluble IL-6R to HepG2 cells. Using a cDNA expression array, mRNA levels of about 580 human genes were tested by differential display analysis. Our findings suggest, that elevation of surface density of IL-6R by attachment of sIL-6R induces major modulation in gene expression profile of the hepatoma cells. Soluble IL-6R alone has minor effect, it rather decreases expression of some genes, while incubation with IL-6 and sIL-6R together induces major changes in the mRNA pattern of HepG2 cells. These data strongly suggest that presence and binding of soluble cytokine receptors are important elements of inter-cytokine cross talk and affects actual gene expression profile of responding cells.