The Devil in the Details: The Emerging Role of Anticitrulline Autoimmunity in Rheumatoid Arthritis

Dihydroarteannuin Ameliorates Collagen-Induced Arthritis Via Inhibiting B Cell Activation by Activating the FcγRIIb/Lyn/SHP-1 Pathway

Background: Dihydroarteannuin (DHA), which is extracted from the traditional Chinese herb Artemisia annua L, exhibits potent immunosuppressive activity in rheumatoid arthritis (RA). Strong evidence indicates that B cells act as an essential factor in the pathogenesis of RA, but research on the immunosuppressive function of DHA in regulating B cells is limited. Objective: To investigate the modulatory effects of DHA on joint destruction, proinflammatory cytokine production, activation, apoptosis and proliferation of B cells and to explore the possible associated mechanism in RA treatment. Methods: Collagen-induced arthritis (CIA) model was established. Weight and joint oedema were record weekly, and joint damage was detected by micro-CT scan. Human Burkitt B lymphoma cells lacking endogenous Fc gamma receptor b (FcγRIIb) gene were transfected with a 232Thr loss-of-function mutant to construct a mutant cell model ST486. The proliferation of ST486 cells was assessed with Cell Counting Kit-8. Apoptosis and activation were tested by flow cytometry. The effects of DHA on the activation of FcγRIIb, protein tyrosine kinases (Lyn), and SH2-containing tyrosine phosphatase-1 (SHP-1) signaling pathways were determined by western blotting. Results: In comparison to model group, bone volume/tissue volume (BV/TV) and bone mineral density (BMD) were increased, whereas joint oedema was decreased in both of the DHA and MTX group. The mRNA and protein expression levels of Interleukin-6 (IL-6) and Tumor necrosis factor-alpha (TNF-α) were decreased after treatment with DHA. In addition, DHA treatment promoted the apoptosis, inhibited the activation and proliferation of ST486 cells. Furthermore, the protein expression levels of FcγRIIb, SHP-1, and Lyn were increased after treatment with DHA. Moreover, the expression of phosphorylated CD19 was also inhibited by DHA. Conclusion: We provide the first evidence that DHA may alleviate collagen-induced arthritis by activating the FcγRIIb/Lyn/SHP-1 signaling pathway in B cell, indicating that DHA is a novel and valuable candidate for RA therapy.

Treatment journey in rheumatoid arthritis with biosimilars: from better access to good disease control through cost savings and prevention of nocebo effects

Early diagnosis and treatment of rheumatoid arthritis (RA) are of critical importance to halt the progression of the disease. Optimal use of advanced imaging techniques or biomarkers may facilitate early diagnosis of RA. Even though many disease-modifying anti-rheumatic drugs (DMARDs) are available for RA treatment, biological DMARDs (bDMARDs) offer expanding therapeutic options and good outcomes in patients with RA who do not have a sufficient response to conventional synthetic DMARDs. However, high costs of bDMARDs have limited patient access to optimised disease management and increased the cost burden for healthcare systems. The advent of biosimilars led to significant cost savings driven by price competition among the reference products, which could be beneficial for healthcare systems. Healthcare provider (HCP)–patient communication and informed shared decision-making are crucial to prevent the occurrence of a nocebo effect, which results from negative perceptions that patients may have and could lead to less effective outcomes. Research has demonstrated that effective communication between HCPs and patients utilising positive framing can improve acceptance by patients to be initiated on or switched to a biosimilar and can help to integrate biosimilars into routine clinical practice to maximise benefits for patients with RA.

Anti-cyclic citrullinated peptide antibody in psoriatic arthritis: a meta-analysis of its frequency and association with clinical features

OBJECTIVE

This study aimed to investigate the frequency of the anti-cyclic citrullinated peptide (anti-CCP) antibody in patients with psoriatic arthritis (PsA) and to assess its associations with clinical features of this disease.

METHODS

The Medline, EMBASE, and Cochrane databases were searched for studies that examined anti-CCP antibodies in patients with PsA. Meta-analyses of the frequency of the anti-CCP antibody in these patients and its association with polyarthritis, bone erosion, dactylitis, and enthesitis were then performed.

RESULTS

Fourteen studies with a combined total of 3291 patients with PsA met the inclusion criteria for this meta-analysis. The pooled overall frequency of anti-CCP antibodies was 9.8% (95% confidence interval [CI] = 7.1-13.3, p < 0.001). Stratification by ethnicity showed that the anti-CCP antibody frequency was lower in Europeans than in non-Europeans (8.5% vs. 14.0%). The meta-analysis showed a significant association of the anti-CCP antibody with polyarthritis (odds ratio [OR] = 4.390, 95% CI = 2.312-8.333, p < 0.001), bone erosion (OR = 2.800, 95% CI = 1.921-4.081, p < 0.001), and dactylitis (OR = 1.958, 95% CI = 1.340-2.861, p < 0.001). However, there was no association between this antibody and enthesitis.

CONCLUSIONS

Our meta-analysis demonstrated that the overall frequency of the anti-CCP antibody was 9.8% in patients with PsA, and its presence was associated with increased risks of polyarthritis, bone erosion, and dactylitis, but not of enthesitis.

The cancer immunotherapy environment may confound the utility of anti-TIF-1γ in differentiating between paraneoplastic and treatment-related dermatomyositis. Report of a case and review of the literature

With the advent of immunotherapy and with the expanding spectrum of malignancies treated with immunomodulatory agents, a new kind of adverse events has come under the spotlight. Clinicians have to be aware of immune-related adverse events and their clinical manifestations. Immunotherapy has been strongly associated with endocrinopathies, gastrointestinal, pulmonary, cutaneous, and renal toxicities but the incidence of rheumatologic adverse events is lower compared to the aforementioned systems. Dermatomyositis is an autoimmune myopathy which has been correlated to underlying evident or occult malignancies. Apart from its characteristic symptoms and signs, the presence of specific antibodies such as anti-transcriptional intermediary factor 1γ (anti-TIF 1γ) usually supports the diagnosis of paraneoplastic nature of the disease. However, a solid distinction between paraneoplastic syndrome and immune-related adverse event is still missing and remains to be elucidated. We here present a case of dermatomyositis in a male patient who underwent four cycles of combined ipilimumab and nivolumab immunotherapy. This is, to our knowledge, the first case of dermatomyositis following combined immune checkpoint inhibition therapy.

Abberant Immunoglobulin G Glycosylation in Rheumatoid Arthritis by LTQ-ESI-MS

Aberrant glycosylation has been observed in many autoimmune diseases. For example, aberrant glycosylation of immunoglobulin G (IgG) has been implicated in rheumatoid arthritis (RA) pathogenesis. The aim of this study is to investigate IgG glycosylation and whether there is an association with rheumatoid factor levels in the serum of RA patients. We detected permethylated N-glycans of the IgG obtained in serum from 44 RA patients and 30 healthy controls using linear ion-trap electrospray ionization mass spectrometry (LTQ-ESI-MS), a highly sensitive and efficient approach in the detection and identification of N-glycans profiles. IgG N-glycosylation and rheumatoid factor levels were compared in healthy controls and RA patients. Our results suggested that total IgG purified from serum of RA patients shows significantly lower galactosylation (p = 0.0012), lower sialylation (p < 0.0001) and higher fucosylation (p = 0.0063) levels compared with healthy controls. We observed a positive correlation between aberrant N-glycosylation and rheumatoid factor level in the RA patients. In conclusion, we identified aberrant glycosylation of IgG in the serum of RA patients and its association with elevated levels of rheumatoid factor.

Association of the Shared Epitope, Smoking and the Interaction Between the Two With the Presence of Autoantibodies (Anti-CCP and RF) in Patients With Rheumatoid Arthritis in a Hospital in Seville, Spain

OBJECTIVES

To evaluate the association of shared epitope, smoking and their interaction on the presence of autoantibodies (anti-cyclic citrullinated peptide [CCP] antibodies and rheumatoid factor) in patients with rheumatoid arthritis in our geographical area.

METHODS

A descriptive and cross-sectional study was carried out in a cohort of 106 patients diagnosed with RA. Odds ratios (OR) for antibody development were calculated for shared epitope, tobacco exposure and smoking dose. Statistical analysis was performed with univariate and multivariate statistics using ordinal logistic regression. Odds ratios were calculated with 95% confidence interval (95% CI) and a value of P<.05 was considered significant.

RESULTS

In univariate analysis, shared epitope (OR=2.68; 95% CI: 1.11-6.46), tobacco exposure (OR=2.79; 95% CI: 1.12-6.97) and heavy smoker (>20 packs/year) (OR=8.93; 95% CI: 1.95-40.82) were associated with the presence of anti-CCP antibodies. For rheumatoid factor, the association was only significant for tobacco exposure (OR=3.89; 95% CI: 1.06-14.28) and smoking dose (OR=8.33; 95% CI: 1.05-66.22). By ordinal logistic regression analysis, an association with high titers of anti-CCP (>200U/mL) was identified with South American mestizos, patients with homozygous shared epitope, positive FR and heavy smokers.

CONCLUSIONS

Being a South American mestizo, having a shared epitope, rheumatoid factor positivity and a smoking dose>20 packs/year are independent risk factors for the development of rheumatoid arthritis with a high titer of anti-CCP (>200U/mL). In shared epitope-positive rheumatoid arthritis patients, the intensity of smoking is more strongly associated than tobacco exposure with an increased risk of positive anti-CCP.

Immune Checkpoint Inhibitors-related Rheumatic Diseases: What Rheumatologist Should Know?

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Immune checkpoint inhibitors are revolutionized drugs for cancer immunotherapy in the last years. The mechanism of action of CPIs including the limitation of the activation of Tcells, and thus enhancing the self-immune response against tumour cells. Checkpointinhibitors( CPIs) may dysregulate the immune system, resulting in some toxicities. These toxicities or side effects are called Immune-related Adverse Events (IRAEs) that can potentially affect any organ and tissue. Rheumatic diseases due to checkpoint inhibitors are also reported in the literature. The spectrum of rheumatic manifestations are quite wide; the most common are arthralgia/arthritis, myalgia/myositis, polimyalgia rheumatica, lupus, rheumatoid arthritis, Sjögren’s syndrome. At the same time, these drugs can also cause an exacerbation of known rheumatologic disease. Treatment approaches for developing rheumatic findings due to checkpoint inhibitors should be multidisciplinary. There should be a close relationship between oncologists who follow-up these patients and rheumatologists. The rheumatic manifestations should be defined and treated early. In general, the musculoskeletal side effects are transient and may regress after stopping CPIs. The most commonly used medications are corticosteroids. Immunosuppressive drugs (HQ, MTX, anti-TNF-alpha, anti-IL-6) should be preferred when treatment is unresponsive or as steroid-sparing agents.

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The aim of this review was to evaluate the checkpoint inhibitors-related rheumatologic findings and therapeutic strategies in light of recent literature data.

Possible role of β-galactosidase in rheumatoid arthritis

Objective: To investigate the potential role of β-galactosidase in altering immunoglobulin G (IgG) galactosylation in serum of rheumatoid arthritis (RA).Methods: The expression level and activity of β-galactosidase in serum and CD 19⁺ B cells were measured by enzyme-linked immune sorbent assay (ELISA). The effect of β-galactosidase on the N-glycan changes in serum from mice intravenously treated with β-galactosidase was observed by linear ion-trap quadrupole-electrospray ionization mass spectrometry (LTQ-ESI-MS). We established a collagen-induced arthritis (CIA) rat model to explore the biological function of β-galactosidase in RA.Results: The expression level of β-galactosidase in serum of 32 patients was elevated when compared with those of 30 healthy controls. The activity and expression level of β-galactosidase in CD19⁺ B cells from RA patients was higher than those from healthy controls. The ratio of m/z 1142/937 was reduced in mice treated with β-galactosidase when compared with normal mice. We found that β-galactosidase was implicated in the development of inflammation by affecting body weight and elevating the expression level of interleukin-6, tumor necrosis factor-α, and rheumatoid factor in the serum.Conclusions: Our results suggested the high level of β-galactosidase in B cells and serum of RA patients and revealed that altered β-galactosidase may be implicated in the progression of inflammation.

The risk of immune-related endocrine disorders associated with anti-PD-1 inhibitors therapy for solid tumors: A systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis to evaluate the risk of immune-related endocrine disorders associated with PD-1 inhibitors therapy for solid tumors.

METHODS

An Embase and PubMed search through December 6, 2017, using the following keywords was performed: immune-related endocrine disorders, and PD-1 inhibitors, etc. The data were analyzed using R 3.4.3 (R Project) and the metafor package. Patients treated with chemotherapy alone were used as control for the purpose of comparison.

RESULTS

A total of 12 clinical trials including 5577 patients were found eligible for the meta-analysis. Compared with chemotherapy, the risk ratios of all-grade endocrine disorders are 13.89, (95% CI: 5.35-36.05, p < 0.001) for nivolumab therapy, and 9.85, (95% CI: 5.65-17.17, p < 0.001) for pembrolizumab therapy. The risk of all-grade hypothyroidism and hyperthyroidism incidence was increased for nivolumab therapy (hypothyroidism: RR 10.07, 95% CI: 3.37-30.11, p < 0.001; hyperthyroidism: RR 4.29, 95% CI: 1.13-16.30, p = 0.034) and for pembrolizumab therapy (hypothyroidism: RR 7.73, 95% CI: 3.86-15.49, p < 0.001; hyperthyroidism: RR 5.09, 95% CI: 2.36-10.97, p < 0.001). There was a significant increase in the risk of grade 1-5 endocrine disorders incidence for ipilimumab-nivolumab combination therapy (versus ipilimumab, RR 3.20, 95% CI: 2.08-4.91, p < 0.001; versus nivolumab, RR 2.54, 95% CI: 1.70-3.80, p < 0.001).

CONCLUSIONS

Both nivolumab and pembrolizumab therapy could result in a higher risk of all-grade immune-related endocrine disorders than chemotherapy. Nivolumab and ipilimumab combination therapy could result in an even higher risk of all-grade immune-related endocrine disorders than ipilimumab or nivolumab alone. Awareness of these side effects could guide clinicians to better manage the patients treated with anti-PD-1 inhibitors therapy for solid tumors.

The Development of Benzimidazole-Based Clickable Probes for the Efficient Labeling of Cellular Protein Arginine Deiminases (PADs)

Citrullination is the post-translational hydrolysis of peptidyl-arginines to form peptidyl-citrulline, a reaction that is catalyzed by the protein arginine deiminases (PADs), a family of calcium-regulated enzymes. Aberrantly increased protein citrullination is associated with a slew of autoimmune diseases (e.g., rheumatoid arthritis (RA), multiple sclerosis, lupus, and ulcerative colitis) and certain cancers. Given the clear link between increased PAD activity and human disease, the PADs are therapeutically relevant targets. Herein, we report the development of next generation cell permeable and "clickable" probes (BB-Cl-Yne and BB-F-Yne) for covalent labeling of the PADs both in vitro and in cell-based systems. Using advanced chemoproteomic technologies, we also report the off targets of both BB-Cl-Yne and BB-F-Yne. The probes are highly specific for the PADs, with relatively few off targets, especially BB-F-Yne, suggesting the preferential use of the fluoroacetamidine warhead in next generation irreversible PAD inhibitors. Notably, these compounds can be used in a variety of modalities, including the identification of off targets of the parent compounds and as activity-based protein profiling probes in target engagement assays to demonstrate the efficacy of PAD inhibitors.

Gene and Protein Expression Profiles in a Mouse Model of Collagen-Induced Arthritis

The risk of rheumatoid arthritis (RA), an autoimmune disease, in the elderly population increases along with that of atherosclerosis, cardiovascular disease, type 2 diabetes, and Alzheimer's disease. Identifying specific biomarkers for RA can clarify the underlying molecular mechanisms and can aid diagnosis and patient care. To this end, the present study investigated the genes and proteins that are differentially expressed in RA using a mouse collagen-induced arthritis (CIA) model. We performed gene microarray and proteome array analyses using blood samples from the mice and found that 50 genes and 24 proteins were upregulated and 48 genes were downregulated by more than 2-fold in the CIA model relative to the control. The gene microarray and proteome array results were validated by evaluating the expression levels of select genes and proteins by real-time PCR and western blotting, respectively. We found that the level of integrin α2, which has not been previously reported as a biomarker of RA, was significantly increased in CIA mice as compared to controls. These findings provide a set of novel biomarkers that can be useful for diagnosing and evaluating the progression of RA.

Is there a relationship between spondyloarthritis and periodontitis? A case-control study

Objective

To compare the frequency and severity of periodontitis in patients with spondyloarthritis (SpA) with healthy control individuals, through the evaluation of clinical, serological and microbiological periodontal condition.

Methods

Patients with a diagnosis of SpA (n=78) and biological disease-modifying antirheumatic drug (bDMARD) naive fulfilling the Assessment of SpondyloArthritis international Society (ASAS) classification criteria as well as 156 healthy controls matched for age/gender were included. Two trained and calibrated periodontologists performed the periodontal clinical assessment. The presence of periodontitis and its severity were determined according to the criteria established by the Centers for Disease Control and Prevention-American Academy of Periodontology. The clinical periodontal variables, IgG1/IgG2 antibodies against Porphyromonas gingivalis andperiodontopathic bacterial identification, were also established. Comparisons of periodontal characteristics between the patients with SpA and the control group were performed using univariable analyses. A logistic regression analyses was performed to calculate the OR (95% CI) for diagnosis of periodontitis in patients with SpA and matched controls.

Results

A diagnosis of periodontitis was established in 56% in patients with SpA versus 69% of healthy controls (P≤ 0.01). Severe periodontitis was found in 3% versus 12% in SpA versus healthy controls, respectively (P≤ 0.01). There was no significant increase of frequency of any periodontal variable, IgG1/IgG2 antibodies against P. gingivalis or the presence of periodontopathic bacteria between patients with SpA and control group. Periodontitis was not positively associated with a diagnosis of SpA (OR: 0.57, 95% CI 0.32 to 1.00, P=0.05) in the logistic regression analyses.

Conclusions

We found a lower rather than a higher frequency and severity of periodontitis in patients with SpA in comparison with healthy control individuals. Our findings suggest that there is no positive association between SpA and periodontitis in Colombian patients.

Antihistone Autoantibodies in Dobermans With Hepatitis

Background

Immune system involvement is suggested as an underlying cause for Doberman hepatitis (DH) based on female predisposition, lymphocyte infiltration, abnormal hepatocyte expression of major histocompatibility complex class II antigens, and homozygosity for dog leukocyte antigen DRB1*00601.

Objective

To measure serum antinuclear antibodies (ANA) and serum antihistone antibodies (AHA) in Dobermans with hepatitis. To determine whether increased serum ANA or serum AHA could be used to support the diagnosis of Doberman hepatitis (DH).

Animals

Privately owned 25 subclinically and 13 clinically affected DH Dobermans and 17 healthy control Dobermans.

Methods

Case–control study. Indirect immunofluorescence (IIF) microscopy and line blot tests were employed for the ANA pilot studies and an enzyme‐linked immunosorbent assay (ELISA) assay for detection of IgG AHA.

Results

Indirect immunofluorescence revealed ANA‐positive cases, and line blot showed AHA reactivity. In ELISA, importantly increased concentrations of AHA were found in 92% (23/25) of dogs in the subclinical stage and 84.6% (11 of 13) of dogs in the clinical stage of DH compared with no control dogs (0/17) (P < 0.0005). The mean AHA absorbance values of the blood samples obtained from the 25 subclinical DH dogs (1.36 ± 0.60, mean ± SD) and the 13 clinically affected dogs (1.46 ± 0.49) were significantly higher than in 17 control dogs (0.51 ± 0.18; P < 0.0001).

Conclusions and Clinical Importance

As the presence of AHA indicates autoimmune activity, our results favor an autoimmune background as one cause for DH. Antihistone antibody could represent a novel means for screening Dobermans with increased serum alanine transaminase concentrations and suspicion of DH.

Cellular and molecular perspectives in rheumatoid arthritis

Synovial immunopathology in rheumatoid arthritis is complex involving both resident and infiltrating cells. The synovial tissue undergoes significant neovascularization, facilitating an influx of lymphocytes and monocytes that transform a typically acellular loose areolar membrane into an invasive tumour-like pannus. The microvasculature proliferates to form straight regularly-branching vessels; however, they are highly dysfunctional resulting in reduced oxygen supply and a hypoxic microenvironment. Autoantibodies such as rheumatoid factor and anti-citrullinated protein antibodies are found at an early stage, often before arthritis has developed, and they have been implicated in the pathogenesis of RA. Abnormal cellular metabolism and mitochondrial dysfunction thus ensue and, in turn, through the increased production of reactive oxygen species actively induce inflammation. Key pro-inflammatory cytokines, chemokines and growth factors and their signalling pathways, including nuclear factor κB, Janus kinase-signal transducer, are highly activated when immune cells are exposed to hypoxia in the inflamed rheumatoid joint show adaptive survival reactions by activating. This review attempts to highlight those aberrations in the innate and adaptive immune systems including the role of genetic and environmental factors, autoantibodies, cellular alterations, signalling pathways and metabolism that are implicated in the pathogenesis of RA and may therefore provide an opportunity for therapeutic intervention.

Association of PTPN22 Haplotypes (-1123G>C/+1858C>T) with Rheumatoid Arthritis in Western Mexican Population

Rheumatoid arthritis (RA) is an autoimmune disease characterized by the presence of antibodies against cyclic citrullinated peptide (anti-CCP), a consequence of the breakdown of immune tolerance. The lymphoid tyrosine phosphatase (Lyp) protein has significant effects on maintenance of peripheral immune tolerance. Two polymorphic variants (-1123G>C and +1858C>T) at PTPN22 gene that encodes this protein have been associated with autoimmune disorders and found in strong linkage disequilibrium in Caucasian population. We evaluated whether PTPN22 haplotypes (-1123G>C/+1858C>T) are associated with anti-CCP antibodies, as well as susceptibility to RA in a Western Mexican population. A total of 315 RA patients and 315 control subjects (CS) were included. The polymorphisms were genotyped by PCR-RFLP and the anti-CCP antibodies were determined by ELISA. The PTPN22 polymorphisms were in strong linkage disequilibrium (D' = 1.00 in CS). The susceptibility haplotype CT was significantly more frequent in RA patients than in CS (OR 2.18, 95% CI 1.15-4.16, p = 0.01). No association between haplotypes and anti-CCP antibodies levels was observed. In conclusion, this study confirmed that -1123G>C and +1858C>T PTPN22 polymorphisms are in strong linkage disequilibrium and the CT haplotype is a susceptibility marker to RA in Western Mexico. However, the PTPN22 haplotypes are not associated with anti-CCP antibodies.

Polyspecificity of Anti-lipid A Antibodies and Its Relevance to the Development of Autoimmunity

The process of natural selection favours germ-line gene segments that encode CDRs that have the ability to recognize a range of structurally related antigens. This presents an immunological advantage to the host, as it can confer protection against a common pathogen and still cope with new or changing antigens. Cross-reactive and polyspecific antibodies also play a central role in autoimmune responses, and a link has been shown to exist between auto-reactive B cells and certain bacterial infections. Bacterial DNA, lipids, and carbohydrates have been implicated in the progression of autoimmune diseases such as systemic lupus erythematosus. As well, reports of anti-lipid A antibody polyspecificity towards single-stranded DNA together with the observed sequence homology amongst isolated auto- and anti-lipid A antibodies has prompted further study of this phenomenon. Though the lipid A epitope appears cryptic during Gram-negative bacterial infection, there have been several reported instances of lipid A-specific antibodies isolated from human sera, some of which have exhibited polyspecificity for single stranded DNA. In such cases, the breakdown of negative selection through polyspecificity can have the unfortunate consequence of autoimmune disease. This review summarizes current knowledge regarding such antibodies and emphasizes the features of S1-15, A6, and S55-5, anti-lipid A antibodies whose structures were recently determined by X-ray crystallography.

Are obesity, ACPAs and periodontitis conditions that influence the risk of developing rheumatoid arthritis in first-degree relatives?

The aim of this study was to investigate the body mass index (BMI), anti-citrullinated protein antibodies (ACPAs) status and the presence of periodontitis and IgG-1/IgG-2 antibodies against Porphyromonas gingivalis (Pg) in the first-degree relatives (FDRs) of rheumatoid arthritis (RA) patients and compare these variables with a control group of healthy individuals from the general population. In total, 100 FDR individuals and 200 healthy controls matched by age and gender were included. Rheumatologic and periodontal assessment was performed, and the presence of ACPAs and anti-P. gingivalis antibodies was evaluated. Groupwise comparisons were analysed using the McNemar and Wilcoxon tests. A conditional logistic regression analysis was performed to establish the associations between BMI, ACPAs and periodontitis in both groups. In the FDR group, 70% of the subjects were female, with a mean age of 37.3 ± 13 years. Obesity was observed in 17 and 7% of the FDRs and controls, respectively. ACPAs were found in 7% of the FDRs vs. 2.5% of the controls. Periodontitis was diagnosed in 79 and 56% of the FDRs and controls, respectively. Among the FDRs, 15% had severe periodontitis. There were associations in the FDR group related to the presence of obesity (OR 2.93, 95% CI 1.03-8.28), ACPAs (OR 2.45, 95% CI 0.7-8.32) and periodontitis (OR 3.70 95% CI 1.89-7.29). Regarding anti-P. gingivalis antibodies and smoking history, no differences were found between the groups. Obesity, ACPAs and periodontitis (diagnosis and severity) can be considered as relevant conditions associated with the development of RA in FDRs.

Association of the polymorphisms of TRAF1 (rs10818488) and TNFAIP3 (rs2230926) with rheumatoid arthritis and systemic lupus erythematosus and their relationship to disease activity among Egyptian patients

Aim of the study

Recent studies demonstrated the association of tumor necrosis factor α-induced protein 3 (TNFAIP3) (rs2230926) and tumor necrosis factor receptor associated factor 1 (TRAF1) (rs10818488) with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in different populations. We aimed at determining whether they confer susceptibility to SLE and RA in Egyptian population and if there is any relation to disease activity and auto-antibodies profile.

Material and methods

A case-control study involving 105 individuals with RA, 90 with SLE and 75 healthy controls was performed using TaqMan genotyping assay for two SNPs that showed the best evidence of association in the previous Caucasian studies.

Results

We detected significant differences in G allele frequency of TNFAIP3 (rs2230926) with SLE (p = 0.017^*) and RA (OR = 2.333; 95% CI: 1.103-4.935, p = 0.023^*) and association with RA disease activity (< 0.001). The A allele of TRAF1 was significantly increased in RA compared to controls(p = 0.049) and with RA activity (p = 0.001), while TRAF1 polymorphism did not exhibit any significant difference in the frequencies of genotypes or alleles in SLE and control (p = 0.280).

Conclusions

TNFAIP3 is a susceptibility gene to SLE and RA in the Egyptian population and is correlated to disease activity and the presence of autoantibodies while TRAF1 polymorphisms increase the risk of RA but not to SLE in Egyptian populations.

Anti-citrullinated peptide antibodies and their value for predicting responses to biologic agents: a review

Anti-citrullinated peptide antibodies (ACPAs) play an important pathogenic role both at the onset and during the disease course. These antibodies precede the clinical appearance of rheumatoid arthritis (RA) and are associated with a less favorable prognosis, both clinically and radiologically. The objective of this work was to conduct a comprehensive review of studies published through September 2015 of ACPAs' role as a predictor of the therapeutic response to the biological agents in RA patients. The review also includes summary of the biology and detection of ACPAs as well as ACPAs in relation to joint disease and CV disease and the possible role of seroconversion. The reviews of studies examining TNF inhibitors and tocilizumab yielded negative results. In the case of rituximab, the data indicated a greater probability of clinical benefit in ACPA(+) patients versus ACPA(-) patients, as has been previously described for rheumatoid factor. Nonetheless, the effect is discreet and heterogeneous. Another drug that may have greater effectiveness in ACPA(+) patients is abatacept. Some studies have suggested that the drug is more efficient in ACPA(+) patients and that those patients show greater drug retention. In a subanalysis of the AMPLE trial, patients with very high ACPA titers who were treated with abatacept had a statistically significant response compared to patients with lower titers. In summary, the available studies suggest that the presence of or high titers of ACPA may predict a better response to rituximab and/or abatacept. Evidence regarding TNFi and tocilizumab is lacking. However, there is a lack of studies with appropriate designs to demonstrate that some drugs are superior to others for ACPA(+) patients.

A Transmembrane Polymorphism of Fcγ Receptor IIb Is Associated with Kidney Deficiency Syndrome in Rheumatoid Arthritis

Objective. The purpose is to investigate the role of kidney deficiency and the association between kidney deficiency and a polymorphism FcγRIIb 695T>C coding for nonsynonymous substitution IIe232Thr (I232T) in rheumatoid arthritis (RA). Methods. Clinical parameters and autoantibodies were analyzed and genotyping was performed in 159 kidney deficiency and 161 non-kidney-deficiency RA patients. Results. The age of disease onset and disease duration exhibited significant differences between two groups (P < 0.01). Patients with kidney deficiency tend to have higher activity of disease (P < 0.05). Anti-cyclic citrullinated peptides antibodies (ACPA) levels of patients with kidney deficiency were higher than the controls (P = 0.039). 125 (78.6%) kidney deficiency and 114 (70.8%) non-kidney-deficiency patients had both ACPA-positive and RF-positive (P = 0.04, OR = 3.29). FcγRIIb I232TT homozygotes were identified in 10 of 159 (6.3%) kidney deficiency subjects and 1 of 161 (0.6%) controls (P = 0.000, OR = 16.45). Furthermore, in pooled genotype analysis, I232IT and I232TT homozygotes were significantly enriched in kidney deficiency individuals compared with the controls (P = 0.000, OR = 3.79). Frequency of T allele was associated with kidney deficiency RA population (P = 0.000, OR = 3.18). Conclusion. This study confirmed that kidney deficiency was closely associated with disease activity and autoimmune disorder in RA. Kidney deficiency in RA is first to reveal a strong genetic link to FcγRIIb variants.

The link between periodontal disease and rheumatoid arthritis: an updated review

Porphyromonas gingivalis is a leading pathogen in chronic periodontitis, a disease process involving progressive destruction of the tissues that support the teeth. Recently, the organism has been reported to produce a unique bacterial enzyme, P. gingivalis peptidyl-arginine deiminase (PPAD), which has the ability to convert arginine residues in proteins to citrulline. Protein citrullination alters protein structure and function; hence, PPAD may be involved in deregulation of the host’s signalling network and immune evasion. Further, accumulating evidence suggests a role for autoimmunity against citrullinated proteins in the development of rheumatoid arthritis (RA). As inflammatory conditions in the lungs of cigarette smokers contribute to the breakdown of immune tolerance to citrullinated epitopes, chronic exposure to citrullinated proteins at periodontitis sites may also predispose susceptible individuals to the development of autoantibodies and the initiation of RA. In this review, we discuss evidence that PPAD may represent a mechanistic link between periodontitis and RA, diseases that are known to be significantly associated at the epidemiological level.

Urinary proteome profile predictive of disease activity in rheumatoid arthritis

Current serum biomarkers for rheumatoid arthritis (RA) are not highly sensitive or specific to changes of disease activities. Thus, other complementary biomarkers have been needed to improve assessment of RA activities. In many diseases, urine has been studied as a window to provide complementary information to serum measures. Here, we conducted quantitative urinary proteome profiling using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and identified 134 differentially expressed proteins (DEPs) between RA and osteoarthritis (OA) urine samples. By integrating the DEPs with gene expression profiles in joints and mononuclear cells, we initially selected 12 biomarker candidates related to joint pathology and then tested their altered expression in independent RA and OA samples using enzyme-linked immunosorbent assay. Of the initial candidates, we selected four DEPs as final candidates that were abundant in RA patients and consistent with those observed in LC-MS/MS analysis. Among them, we further focused on urinary soluble CD14 (sCD14) and examined its diagnostic value and association with disease activity. Urinary sCD14 had a diagnostic value comparable to conventional serum measures and an even higher predictive power for disease activity when combined with serum C-reactive protein. Thus, our urinary proteome provides a diagnostic window complementary to current serum parameters for the disease activity of RA.

Association of anticyclic citrullinated peptide antibodies and/or rheumatoid factor status and clinical presentation in early arthritis: results from the ESPOIR cohort

OBJECTIVE

To compare the initial clinical, biological, and radiographic findings of early arthritis by positivity for rheumatoid factor (RF) and/or anticyclic citrullinated peptide antibodies (anti-CCP), and to validate a patient profile based on this serologic information.

METHODS

The ESPOIR cohort comprises patients presenting synovitis of at least 2 joints for 6 weeks to 6 months. Patients underwent testing for IgM rheumatoid factor (IgM-RF) and anti-CCP2 antibodies and were divided into 4 groups: RF- and anti-CCP- (group 1), RF+ and anti-CCP- (group 2), RF- and anti-CCP+ (group 3), RF+ and anti-CCP+ (group 4). We compared the groups in terms of clinical, biological, and radiographic features (baseline scores and 6-month and 12-month progression).

RESULTS

Of the 813 recruited patients, 406 (50%) were in group 1, 91 (11.2%) in group 2, 34 (4.1%) in group 3, and 281 (34.6%) in group 4. Mean baseline erythrocyte sedimentation rate and C-reactive protein were higher for anti-CCP+ groups (groups 3 and 4) than for other groups (p < 0.001), and van der Heijde-modified Sharp score for radiographs was higher for group 4 than for other groups (p < 0.001). Clinical presentation was not consistently associated with serologic profile. Radiographic progression at 1 year was higher for anti-CCP+ groups than other groups (p < 0.001).

CONCLUSION

The phenotype of patients with early arthritis with or without anti-CCP and/or RF positivity did not correspond to a particular clinical presentation. However, baseline acute-phase reactants and short-term radiographic progression were high in patients with anti-CCP positivity, which may be associated with the inflammatory process and progressive disease in patients with early arthritis.

Gene-environmental interaction between smoking and shared epitope on the development of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis: a meta-analysis

OBJECTIVE

The aim of this study was to determine the gene-environment interactions of smoking and shared epitope (SE) both separately and combined on anti-cyclic citrullinated peptide (CCP) antibodies in patients with rheumatoid arthritis (RA).

METHODS

The literature was searched using the MEDLINE, EMBASE and Cochrane databases. A meta-analysis on the associations between tobacco exposure (TE) and/or SE and the development of anti-CCP antibodies in patients with RA was performed.

RESULTS

Eight comparison studies with 5317 RA patients were considered in this meta-analysis. The odds ratio (OR) for positive anti-CCP antibodies in TE+/SE- patients with RA was increased compared with TE-/SE- patients (OR = 1.373, 95% CI = 1.111-1.698, P = 0.003). The ORs for positive anti-CCP antibodies in TE-/SE+ patients and TE+/SE+ patients with RA were also increased compared with TE-/SE- patients (OR = 2.678, 95% CI = 2.031-3.532, P < 1.0 × 1(0-9) in TE-/SE+; OR = 4.233, 95% CI = 2.458-7.291, P = 1.9 × 10(-8) in TE+/SE+). Stratification by ethnicity indicated the same pattern as that shown in the overall group. The OR for positive anti-CCP antibodies in TE+/SE+ patients with RA was much higher than in TE-/SE- patients in Europeans and Asians (OR = 3.879, 95% CI = 2.203-6.830, P = 2.6 × 10(-7); OR = 10.504, 95% CI = 3.182-34.67, P = 1.1 × 10(-4)).

CONCLUSIONS

This meta-analysis suggests a gene-environmental interaction between smoking and SE for the development of anti-CCP antibodies.

A chronic model of arthritis supported by a strain-specific periarticular lymph node in BALB/c mice

Current animal models of arthritis only partially reflect the complexity of rheumatoid arthritis and typically lack either chronicity or autoantibody formation. Here we describe a model that combines features of antigen-induced arthritis and collagen-induced arthritis, which can be efficiently induced in BALB/c and C57BL/6 mice. However, BALB/c mice generate significantly higher titres of anticollagen and anticitrullinated peptide antibodies, show a stronger progressive joint destruction, and in the chronic phase the disease spreads between joints. Concomitant to the observation of a more severe pathology, we discovered a previously undescribed small periarticular lymph node in close proximity to the knee joint of BALB/c mice, which acts as the primary draining lymph node for the synovial cavity. Our model more closely reflects the pathology of rheumatoid arthritis than classical models of arthritis and is hence particularly suitable for further studies of disease pathogenesis.

The reporting quality of studies investigating the diagnostic accuracy of anti-CCP antibody in rheumatoid arthritis and its impact on diagnostic estimates

BACKGROUND

Recently anti-CCP testing has become popular in the diagnosis of rheumatoid arthritis (RA). However, the inadequate reporting of the relevant diagnostic studies may overestimate and bias the results, directing scientists into making false decisions. The aim of the present study was to evaluate the reporting quality of studies used anti-CCP2 for the diagnosis of RA and to explore the impact of reporting quality on pooled estimates of diagnostic measures.

METHODS

PubMed was searched for clinical studies investigated the diagnostic accuracy of anti-CCP. The studies were evaluated for their reporting quality according to STARD statement. The overall reporting quality and the differences between high and low quality studies were explored. The effect of reporting quality on pooled estimates of diagnostic accuracy was also examined.

RESULTS

The overall reporting quality was relatively good but there are some essential methodological aspects of the studies that are seldom reported making the assessment of study validity difficult. Comparing the quality of reporting in high versus low quality articles, significant differences were seen in a relatively large number of methodological items. Overall, the STARD score (high/low) has no effect on the pooled sensitivities and specificities. However, the reporting of specific STARD items (e.g. reporting sufficiently the methods used in calculating the measures of diagnostic accuracy and reporting of demographic and clinical characteristics/features of the study population) has an effect on sensitivity and specificity.

CONCLUSIONS

The reporting quality of the diagnostic studies needs further improvement since the study quality may bias the estimates of diagnostic accuracy.

Periodontitis, Porphyromonas, and the pathogenesis of rheumatoid arthritis

Epidemiological data indicate a link between rheumatoid arthritis (RA) and periodontal disease (PD). In vitro and in vivo studies have sought to dissect potential mechanisms by which PD may contribute to initiation and progression of RA. However, these are both multifactorial, chronic diseases, and their complex etiologies and pathogenesis themselves remain incompletely understood. Could there really be an etiological link or does this simply represent a statistical coincidence muddied by common risk factors? This review seeks to provide background on these two diseases in the context of recent discoveries suggesting that their pathogenesis may be related. In particular, the process of citrullination, a post-translational protein modification, has been highlighted as a process common to both diseases. The evidence for a relationship between the diseases is explored and its potential mechanisms discussed.

The major risk alleles of age-related macular degeneration (AMD) in CFH do not play a major role in rheumatoid arthritis (RA)

Because activation of the alternative pathway (AP) of the complement system is an important aspect of both age-related macular degeneration (AMD) and rheumatoid arthritis (RA), we wished to address the question whether genetic risk factors of the AP inhibitor complement factor H (CFH) for AMD would also be risk factors for RA. For this purpose we genotyped single nucleotide polymorphisms (SNPs) in a Dutch set of RA patients and controls. Similarly, a meta-analysis using a Spanish cohort of RA as well as six large genome-wide association studies (GWAS) studies was performed. For these SNPs we analysed more than 6000 patients and 20,000 controls. The CFH variants, I62V, Y402H, IVS1 and IVS10, known to associate strongly with AMD, did not show a significant association with the risk of developing RA despite a strong statistical power to detect such differences. In conclusion, the major risk alleles of AMD in CFH do not have a similar effect on developing RA.

Influence of TRAF1/C5 and STAT4 genes polymorphisms on susceptibility and severity of rheumatoid arthritis in Egyptian population

Rheumatoid arthritis (RA) is the most common cause of adult inflammatory arthritis. Recent genome-wide association scans have disclosed several single-nucleotide polymorphisms associated with RA susceptibility. The aim of this study was to determine whether the polymorphisms of TRAF1/C5 (tumor necrosis factor (TNF)-receptor associated factor 1)/(complement component 5) and STAT4 (signal transducers and activators of transcription 4) confer susceptibility, activity and severity to RA in Egyptian populations. One hundred and seventy-two RA patients and 160 controls were enrolled in the study. Polymorphisms of TRAF1/C5 and STAT4 genes were determined using restriction fragment length polymorphism-polymerase chain reaction. The TRAF1/C5 A and STAT4 T alleles were significantly associated with RA in Egyptian population. TRAF1/C5 A allele and STAT4 TT genotype were significantly associated with RA severity. In conclusion the mutant alleles or genotypes of both examined polymorphisms are associated with the development of RA in Egyptian population.

Inhibiting the C5-C5a receptor axis

Activation of the complement system is a major pathogenic event that drives various inflammatory responses in numerous diseases. All pathways of complement activation lead to cleavage of the C5 molecule generating the anaphylatoxin C5a and, C5b that subsequently forms the terminal complement complex (C5b-9). C5a exerts a predominant pro-inflammatory activity through interactions with the classical G-protein coupled receptor C5aR (CD88) as well as with the non-G protein coupled receptor C5L2 (GPR77), expressed on various immune and non-immune cells. C5b-9 causes cytolysis through the formation of the membrane attack complex (MAC), and sub-lytic MAC and soluble C5b-9 also possess a multitude of non-cytolytic immune functions. These two complement effectors, C5a and C5b-9, generated from C5 cleavage, are key components of the complement system responsible for propagating and/or initiating pathology in different diseases, including paroxysmal nocturnal hemoglobinuria, rheumatoid arthritis, ischemia-reperfusion injuries and neurodegenerative diseases. Thus, the C5-C5a receptor axis represents an attractive target for drug development. This review provides a comprehensive analysis of different methods of inhibiting the generation of C5a and C5b-9 as well as the signalling cascade of C5a via its receptors. These include the inhibition of C5 cleavage through targeting of C5 convertases or via the C5 molecule itself, as well as blocking the activity of C5a by neutralizing antibodies and pharmacological inhibitors, or by targeting C5a receptors per se. Examples of drugs and naturally occurring compounds used are discussed in relation to disease models and clinical trials. To date, only one such compound has thus far made it to clinical medicine: the anti-C5 antibody eculizumab, for treating paroxysmal nocturnal hemoglobinuria. However, a number of drug candidates are rapidly emerging that are currently in early-phase clinical trials. The C5-C5a axis as a target for drug development is highly promising for the treatment of currently intractable major human diseases.

A can of red herrings

Lymphomatoid granulomatosis is a rare disease. Anti-cyclic citrullinated peptide (anti-CCP) antibody is more commonly found in patients with rheumatoid arthritis and less frequently in some of the other rheumatic and non-rheumatic conditions. It is not recognized to be present in lymphoproliferative disease on its own. We report the first case of anti-CCP antibody positivity in lymphomatoid granulomatosis presenting with polyarthritis. This case illustrates the evolving nature of this disease and its characteristics at different stages leading to the challenge of an accurate diagnosis in the setting of a paraneoplastic polyarthritis.

The relationship between the presence of anti-cyclic citrullinated peptide antibodies and clinical phenotype in very early rheumatoid arthritis

Background

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are highly specific for RA, but are not detectable in all RA patients. The aim of this study was to establish whether the clinical phenotypes of anti-CCP positive and negative disease are distinct at the earliest clinically apparent phase of disease.

Methods

Patients were recruited from the Birmingham early inflammatory arthritis clinic. Participants were included in the current study if they presented within 3 months of symptom onset and fulfilled 1987 ACR criteria for RA at some point during an 18 month follow-up. Data were collected on demographic variables, joint symptoms and tender (n = 68) and swollen (n = 66) joint counts. CRP, ESR, rheumatoid factor and anti-CCP2 status were measured.

Results

92 patients were included (48 anti-CCP positive). The anti-CCP positive and negative groups were comparable in terms of demographic variables, inflammatory markers, joint counts and 1987 ACR classification criteria, except that more anti-CCP positive patients were rheumatoid factor positive (83.3% vs. 11.4%, p < 0.01). There was no significant difference in the pattern of joint involvement, except for an increased prevalence of knee joint swelling in anti-CCP positive patients (42.9% vs. 22.2%, p = 0.03).

Conclusions

Patients with and without anti-CCP antibodies present in a similar way, even within three months of clinically apparent disease that eventually develops into RA.

Antibodies to mutated citrullinated vimentin in rheumatoid arthritis: diagnostic value, association with radiological damage and axial skeleton affection

Background:

Early definitive diagnosis and effective treatment are mandatory in rheumatoid arthritis (RA) as it can halt the disease progression and subsequent joints destruction.

Objective:

To investigate the diagnostic and prognostic value of anti-mutated citrullinated vimentin (anti-MCV) and its correlation with disease activity, peripheral and axial skeleton affection in RA patients.

Patients and methods:

A total of 123 patients with different rheumatic diseases were enrolled in a prospective-two year study at Ain Shams University hospital: 64 patients with RA and 59 patients with other rheumatic diseases as controls. RA patients were fulfilling the traditional and the new ACR/EULAR diagnostic criteria for RA. They have been followed up for two years. At baseline, all RA patients were subjected to: Clinical assessment of disease activity by taking full histories, general and local examination, measurement of 28 joint count of tender and swollen joints with calculation of disease activity score (DAS-28) for each patient. Complete blood count, erythrocytes sedimentation rate, C-reactive protein and rheumatoid factor titers were performed. Anti-MCV IgG immunoglobulins’ assay was performed at the study endpoint by ELISA. RA patients were then classified into; anti-MCV positive and anti-MCV negative groups for statistical comparison. Plain X-ray was performed on the peripheral joints and scored by the Simple Erosion Narrowing score (SEN-score). Magnetic Resonance Imaging (MRI) scans were carried out to 22 RA patients on cervical and lumbosacral regions.

Results:

Anti-MCV antibodies were found to be of high sensitivity (79.6%) and specificity (96.6%) in diagnosing RA. The area under the curve was 0.893 at 95% confidence interval (CI), confers an odds ratio of 23.5. Anti-MCV positive RA patients had significantly higher DAS-28 and SEN-scores than anti-MCV negative patients; who were found to have more benign disease with lower incidence of erosions (P < 0.05). MRI scans revealed that; 17/22 (77%) had cervical joints involvement while, 8 (36%) had lumbo-sacral joint lesions (P < 0.05), both were correlated significantly with aggressive peripheral joint disease.

Conclusion:

Anti-MCV antibodies are promising diagnostic and prognostic marker in RA, with high sensitivity and specificity. They may identify a subset of RA patients with aggressive early erosive disease. The axial skeleton—especially the cervical spine—could be affected in RA and this was correlated with aggressive peripheral joints’ disease. MRI scanning is a sensitive method for detecting axial skeleton involvement in RA, in attempt for better disease control and outcomes.

Effect of tobacco smoking on tissue protein citrullination and disease progression in patients with rheumatoid arthritis

The aim of the present work was to study the effect of tobacco smoking on disease progression in rheumatoid arthritis patients and its relation to anti-cyclical citrullinated peptide (anti-CCP) antibodies. The study included 54 patients; 20 non-smokers, 9 ex-smokers, 14 mild to moderate smokers and 11 heavy smokers. Fifteen normal volunteers were also studied as controls. Disease stage was clinically and radiologically determined, rheumatoid factor (RF) and anti-CCP antibodies were measured in serum. Higher percentage of severe disease (stage III) was seen in heavy smoker patients than mild to moderate smokers (54.6% versus 35.7%) and in moderate smokers than ex-smokers (35.7% versus 33.6%). Lowest percentage of severe disease was seen in non-smokers (15%). RF and anti-CCP were significantly higher in smoker than non-smoker and in heavy than mild to moderate smoker patients (p < 0.01, p < 0.05 and p < 0.01, p < 0.001, respectively). In smoker patients, both RF and anti-CCP antibodies correlated significantly and positively with smoking index (r = 0.581, p < 0.001; r = 0.661, p < 0.001). Also, smoking index and anti-CCP correlated significantly and positively with disease stage (r = 0.424, p < 0.05; r = 0.523, p < 0.01). It appears from our results that, tobacco smoking mostly play a role in progression of rheumatoid arthritis through tissue protein citrullination. So all rheumatoid arthritis patients must quit completely to achieve a good control.

Contribution of myelin autoantigen citrullination to T cell autoaggression in the central nervous system

Breakdown in immunological self tolerance, leading to autoimmune diseases such as multiple sclerosis, might arise from immune recognition of self proteins that have undergone heightened posttranslational modification under pathophysiological conditions. A posttranslational modification of particular interest is the deimination of Arg to citrulline, catalyzed by peptidylarginyl deiminase (PAD) enzymes. As a CD4(+) T cell-driven model of multiple sclerosis, we used experimental autoimmune encephalomyelitis (EAE) induced with the immunodominant 35-55 peptide of myelin oligodendrocyte glycoprotein (pMOG) in C57BL/6 mice to test whether citrullination of a T cell epitope can contribute to disease etiopathology. Immunization with an altered peptide ligand (APL) of pMOG with an Arg-->citrulline conversion at a TCR contact (residue 41) led to the activation of two populations of APL-responsive T cells that either did, or did not cross-react with the native pMOG peptide. This APL could induce EAE. However, this reflected the activation of T cells that cross-reacted with the native pMOG epitope, because prior tolerization of these T cells using pMOG prevented APL-induced EAE. Using a passive transfer model, we found that T cells that responded specifically to the citrullinated form of pMOG were neither necessary, nor sufficient to initiate the EAE lesion. Nevertheless, these cells could provoke exacerbation of pathology if transferred into mice with ongoing EAE. The PAD2 and PAD4 enzymes were markedly upregulated in the inflamed CNS. Therefore, once inflammation is established, citrullination of target autoantigens can allow an expanded repertoire of T cells to contribute to CNS pathology.

A systematic review and meta-analysis of the efficacy and safety of etanercept for treating rheumatoid arthritis

The aim of this study was to evaluate the efficacy and safety of etanercept (ETA) for treating rheumatoid arthritis. A systematic review was performed to search for randomized clinical trials comparing subcutaneous doses of ETA at 25 mg twice a week or 50 mg weekly to a placebo group, with or without methotrexate. Studies of low quality (less than 3 points on Jadad's scale) were excluded. The efficacy was assessed by using the criteria of the American College of Rheumatology (ACR). Safety data were evaluated based on serious adverse events, serious infections, malignancy and deaths. Withdrawals as a result of adverse events or lack of efficacy were also evaluated. Eight studies met the inclusion criteria, comprising 2385 patients. In the efficacy meta-analysis, a greater number of ETA-treated patients achieved the efficacy criteria within 6 months of treatment, where the relative risk (RR) was 2.94 [2.27, 3.81] for achieving ACR20, 5.28 [3.12, 8.92] for ACR50 and 4.83 [1.74, 13.47] for ACR70. After 1 year, the RR for achieving ACR20, ACR50 and ACR70 were 1.14 [1.07, 1.23], 1.36 [1.21, 1.53] and 1.56 [1.30, 1.88], respectively. This response rates were higher for ETA-treated patients in comparison with control group patients. For safety, there were no statistically significant differences between treated patients and controls. This was also confirmed by withdrawals as a result of adverse events, which were not statistically different between the two groups. However, more patients withdrew from control groups because of a lack of efficacy as compared with ETA groups (RR = 0.48 [0.30, 0.78]).

Antibodies to citrullinated vimentin are a specific and sensitive marker for the diagnosis of rheumatoid arthritis

BACKGROUND

The last 5 years have seen the emergence and establishment of antibodies to citrullinated antigens as the diagnostic marker for rheumatoid arthritis (RA). Initially, these were detected using a synthetic peptide, which has undergone a number of modifications to give a diagnostic test with a sensitivity of 65-80% and a specificity of >95%. Antibodies to citrullinated vimentin were first described in 1994 as a highly specific marker for RA (anti-Sa). However, no easily performed assay for these antibodies has been available.

METHODS

We have examined the use of a ELISA-based assay with a mutated citrullinated vimentin (MCV) antigen (Orgentec, Mainz, Germany) to assess the diagnostic and prognostic utility of this antibody in RA.

RESULTS

Antibodies to MCV were detected in the sera of 74% RA patients (specificity 96%), 2% systemic lupus erythematosus, 14% Sjögren's syndrome, and 2% scleroderma. Anti-MCV was not detected in sera from healthy blood donors. There was no difference in the frequency of antibodies detected in RA patients with early (<2 years) or chronic (>2 years) disease. There was no significant variation in anti-MCV antibody concentrations in early RA patients over a 52-week period. No significant change was observed with time between the two treatment groups of methotrexate alone or methotrexate plus infliximab.

CONCLUSIONS

Antibodies to MCV are a specific and sensitive marker for the diagnosis of RA.

The role of anti-cyclic cytrullinate antibodies testing in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, progressive inflammatory disease, which leads to joint destruction and deformity and is often accompanied by systemic complications. It is generally considered an autoimmune disease characterized by several autoantibodies. The impressive advances made in understanding the biological mechanisms of RA have led to more focused, directed therapies that have joined, and in many cases overcome, more traditional treatments. Along the last decade, the so-called biological anti-TNF-alpha agents have been shown to reduce disease activity, to slow disease progression and to improve patients' quality of life. The clear evidence that an early therapeutic intervention improves the overall outcome of the disease supports the importance of an early diagnosis. In the last years, several studies showed that anti-cyclic citrullinated peptide antibodies (anti-CCP) represent a sensitive and specific serologic marker for RA. Moreover, a large body of evidence has shown that anti-CCP may also serve as an early diagnostic and prognostic marker in RA. The aim of this article is to provide an overview of the current state of knowledge regarding anti-CCP focusing in particular on their clinical specificity and prognostic value in RA.

Anti-CD20 antibody rituximab in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, autoimmune reaction-driven systemic inflammatory disease that affects joints and several other organs. Although anti-TNF therapy and combination therapy with traditional anti-rheumatic drugs have improved the treatment of RA, still quite a significant proportion of patients do not reach adequate anti-rheumatic response. The understanding of the pathogenesis of RA has developed markedly during the last two decades, and this has brought up new targets for anti-rheumatic therapy. B cells have been found to have a pivotal role in the development of arthritis both in experimental models and in humans. Rituximab, an anti-CD20 antibody that depletes B cells, has been introduced in the treatment of RA, and it has proven to be safe and efficacious in RA. This review gives an overview on the mechanism of action of rituximab in RA and summarizes the published clinical data of rituximab in the treatment of RA.

Targeted Synovial Fluid Proteomics for Biomarker Discovery in Rheumatoid Arthritis

Objective

Rheumatoid arthritis (RA) is an autoimmune disease that targets the synovium. The autoantigens involved in the autoantibody responses in RA are unknown. A targeted proteomics approach was used to identify proteins in RA synovial fluid (SF) that are recognized by autoantibodies in RA sera.

Methods

RA SF, depleted of abundant proteins, was fractionated by two-dimensional liquid chromatography (chromatofocusing followed by reverse phase HPLC). Protein arrays constructed from these fractions were probed with RA and normal control sera, and proteins within reactive fractions were identified by mass spectrometry. The reactivity of RA sera to an identified peptide was confirmed by ELISA.

Results

RA sera specifically reacted to a SF fraction containing fibrin. Mass spectrometry analyses established the presence of a citrullinated arginine at position 271 of the fibrin fragment present in RA SF. A synthetic peptide corresponding to fibrin residues 259–287, containing the citrulline substitution at Arg 271, was recognized by 10 of 12 RA sera, but by two of 18 normal control sera and one of 10 systemic lupus erythematosus sera.

Conclusion

Proteomics methodology can be used to directly characterize post-translational modifications in candidate autoantigens isolated from sites of disease activity. The finding that RA sera contain antibodies to the citrullinated fibrin 259–287 peptide may ultimately lead to improved diagnostic tests for RA and/or biomarkers for disease activity.

Autoimmune responses in the rheumatoid synovium

Rene Toes and Tom Huizinga discuss a new study indicating that lymphoneogenesis in the inflamed synovial tissue of patients with rheumatoid arthritis is fostering potentially pathogenic immune responses.

Immunoglobulin 1 (IgG1) Fc-glycosylation profiling of anti-citrullinated peptide antibodies from human serum

In several autoimmune disorders, including rheumatoid arthritis (RA), autoantibodies are thought to be the driving force of pathogenicity. Glycosylation of the Fc-part of human Igs is known to modulate biological activity. Hitherto, glycosylation of human IgG-Fc has been analyzed predominantly at the level of total serum IgG, revealing reduced galactosylation in RA. Given the pathogenic relevance of autoantibodies in RA, we wished, in the present study, to address the question whether distinct Fc-glycosylation features are observable at the level of antigen-specific IgG subpopulations. For this purpose, we have developed a method for the microscale purification and Fc-glycosylation analysis of anti-citrullinated peptide antibodies (ACPA). ACPA represent a group of autoantibodies that occur with unique specificity in RA patients. Their presence is associated with increased inflammatory disease activity and rapid joint destruction. Results indicate that ACPA of the IgG1 subclass vary considerably from total serum IgG1 with respect to Fc-galactosylation, with galactosylation being higher on ACPA than on serum IgG1 for some patients, while other patients show higher galactosylation on serum IgG1 than on ACPA. Using this method, studies can be performed on the biological and clinical relevance of ACPA glycosylation within RA patient cohorts.