Current concepts in the pathogenesis of early rheumatoid arthritis

The effect of smoking on response to methotrexate in rheumatoid arthritis patients: A systematic review and meta-analysis

OBJECTIVES

In the current study, we aimed to investigate the effect of smoking on inadequate response to methotrexate (MTX-IR) in rheumatoid arthritis (RA) patients.

METHODS

We searched PubMed, Embase, and Web of Science until 6 June 2022. Observational or interventional studies investigating MTX-IR in RA patients based on smoking status were included. Two independent reviewers assessed the risk of bias and the certainty of the evidence using the Risk of Bias in Nonrandomized Studies-of Interventions and Grades of Recommendation, Assessment, Development, and Evaluation tools, respectively.

RESULTS

We included 23 studies in the systematic review and 13 in the meta-analysis. Of the 13 included studies, 6 had a moderate risk, 3 had a serious risk, and 4 had a critical risk of bias. The overall random-effect meta-analysis suggested that smokers were 58% more likely to be MTX-IR when compared with nonsmokers [odds ratio (OR) 1.58, 95% confidence interval 1.21-2.06; P = .001; I2 = 69.3%]. The common-effect meta-analysis of the adjusted ORs demonstrated an overall OR of 2.69 (1.88-3.83; P < .001; I2 = 27.1%).

CONCLUSIONS

The current study showed that smoking is a significant predictor of MTX-IR, especially in disease-modifying antirheumatic drug-naïve early RA patients, as most of the included studies in the meta-analysis consisted of this population.

Citrullinated and malondialdehyde-acetaldehyde modified fibrinogen activates macrophages and promotes an aggressive synovial fibroblast phenotype in patients with rheumatoid arthritis

Objective

Post-translational protein modifications with malondialdehyde-acetaldehyde (MAA) and citrulline (CIT) are implicated in the pathogenesis of rheumatoid arthritis (RA). Although precise mechanisms have not been elucidated, macrophage-fibroblast interactions have been proposed to play a central role in the development and progression of RA. The purpose of our study was to evaluate the downstream effects of macrophage released soluble mediators, following stimulation with fibrinogen (FIB) modified antigens, on human fibroblast-like synoviocytes (HFLS).

Methods

PMA-treated U-937 monocytes (Mϕ) and macrophage-differentiated peripheral blood mononuclear cells (MP) were stimulated with FIB, FIB-MAA, FIB-CIT, or FIB-MAA-CIT. HFLS-RA cells were stimulated directly with FIB antigens or with supernatants (SN) from macrophages (Mϕ-SN or MP-SN) stimulated with FIB antigens. Genes associated with an aggressive HFLS phenotype, extracellular matrix proteins, and activated signaling pathways were evaluated.

Results

HFLS-RA cells treated with Mϕ-SNFIB-CIT and Mϕ-SNFIB-MAA-CIT demonstrated significant increases in mRNA expression of genes associated with an aggressive phenotype at 24-h as compared to direct stimulation with the same antigens. Similar results were obtained using MP-SN. Cellular morphology was altered and protein expression of vimentin (p<0.0001 vs. Mϕ-SNFIB) and type II collagen (p<0.0001) were significantly increased in HFLS-RA cells treated with any of the Mϕ-SN generated following stimulation with modified antigens. Phosphorylation of JNK, Erk1/2, and Akt were increased most substantially in HFLS-RA treated with Mϕ-SNFIB-MAA-CIT (p<0.05 vs Mϕ-SNFIB). These and other data suggested the presence of PDGF-BB in Mϕ-SN. Mϕ-SNFIB-MAA-CIT contained the highest concentration of PDGF-BB (p<0.0001 vs. Mϕ-SNFIB) followed by Mϕ-SNFIB-CIT then Mϕ-SNFIB-MAA. HFLS-RA cells treated with PDGF-BB showed similar cellular morphology to the Mϕ-SN generated following stimulation with modified FIB, as well as the increased expression of vimentin, type II collagen, and the phosphorylation of JNK, Erk1/2 and Akt signaling molecules.

Conclusion

Together, these findings support the hypothesis that in response to MAA-modified and/or citrullinated fibrinogen, macrophages release soluble factors including PDGF-BB that induce fibroblast activation and promote an aggressive fibroblast phenotype. These cellular responses were most robust following macrophage activation with dually modified fibrinogen, compared to single modification alone, providing novel insights into the combined role of multiple post-translational protein modifications in the development of RA.

DNA methylation change of HIPK3 in Chinese rheumatoid arthritis and its effect on inflammation

Introduction

Homeodomain-interacting protein kinase 3 (HIPK3) plays an important role in cell proliferation, apoptosis, and inflammation. Over-expression of HIPK3 in immune cells in rheumatoid arthritis (RA) has been reported. In this study, we investigated blood methylation levels and clinical characteristics of RA in a Chinese population.

Methods

A total of 235 patients with RA, 30 with osteoarthritis (OA), and 30 matched healthy controls were recruited. The methylation status of seven CpGs in the differentially methylated region of HIPK3 (cg05501357) was measured using targeted methylation-sequencing technology. The association between methylation haplotypes and the overall methylation status of HIPK3 with clinical characteristics was assessed using generalized linear regression.

Results

All seven CpGs showed hypomethylation status in RA blood compared with OA and normal individuals (overall p= 1.143×10^-8 and FDR= 2.799×10^-7), which is consistent with the previously reported high expression of HIPK3 in RA immune cells. Among all seven CpGs, 33286785 showed the highest predictive power with an area under the curve (AUC) of 0.829; we received a higher AUC=0.864 when we combined HIPK3 with anti-citrullinated protein antibodies (ACPA -) and rheumatoid factor (RF +) in the prediction model, indicating that when a patient's ACPA is negative, HIPK3 can assist RF as a new clinical index for the diagnosis of RA. We also found that HIPK3 methylation levels were negatively correlated with C-reactive protein (CRP; r= -0.16, p= 0.01). Methylation haplotypes were analyzed, and the full methylation haplotype (FMH; r= 0.16, p= 0.01) and full non-methylation haplotype (FNH; r= 0.18, p= 0.0061) were negatively correlated with CRP.

Conclusion

Circulating blood methylation levels in the protein region of HIPK3 can be utilized as a supportive diagnostic biomarker and CRP level indicator for RA.

Expression and clinical significance of the m6A reader YTHDF2 in peripheral blood mononuclear cells from rheumatoid arthritis patients

As an important m6A reader, the YT521-B homology domain family 2 (YTHDF2) has been shown to regulate mRNA degradation and translation, and to be involved in inflammation. However, little is known about the role of YTHDF2 in the autoimmune-based inflammatory disease rheumatoid arthritis (RA). To begin to ascertain any role for this reader, 74 RA patients and 63 healthy controls (HC) were recruited for this study. Blood was collected from each subject and peripheral blood mononuclear cells (PBMC) isolated. Thereafter, mRNA expression of YTHDF2, interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in the cells was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The harvested blood was also assessed for a variety of parameters, including levels of C-reactive protein (CRP), erythrocyte sedimentation rates (ESR), white blood cell counts (WBC), neutrophils counts (N)/neutrophils percentages (N%), and neutrophil:lymphocyte ratios (NLR) - each markers of inflammation during RA. The results showed that YTHDF2 mRNA expression in RA patient PBMC was decreased significantly vs that in healthy control subject cells. Further, YTHDF2 mRNA expression in RA patient PBMC negatively-correlated with ESR, CRP levels, WBC counts, as well as neutrophils counts, percentages, and NLR values. In addition, it was seen that YTHDF2 mRNA expression in RA patient PBMC was associated with host serum RF levels and treatment. Moreover, it was found that mRNA expression of IL-1β, IL-6, IL-8, and TNFα was increased in PBMC from RA patients relative to in control subject cells; however, only the increased IL-1β expression was seen to be negatively-correlated with decreased YTHDF2 mRNA expression. In conclusion, the present study illustrated that YTHDF2 expression might have some regulatory role in the underlying mechanisms associated with the autoimmune disease RA and that this m6A reader could at some point represent a potential target for regulating inflammatory responses that occur during RA.

Use of In silico tools for screening buffers to overcome physical instability of Abatacept

Rheumatoid arthritis is an autoimmune disorder. Abatacept (CTLA4-Ig) is used for the treatment of Rheumatoid arthritis. Abatacept is a monoclonal antibody. Monoclonal antibodies undergo chemical (e.g. oxidation, deamidation, hydrolysis) and physical (e.g. aggregation, unfolding) instabilities while handling and storage. Abatacept is also prone to aggregation. Stabilizing agents such as buffers are used to stabilize monoclonal antibodies. But, the selection of the appropriate buffer is a time-consuming process because after testing many buffers based on the analysis of the results the appropriate buffer is identified. To overcome this issue in the current study computational tools were utilized to virtually screen different buffers to select the appropriate buffer. Ligand binding is the principal mechanism of conformational stability of proteins. For the buffers as well ligand binding is the most common mechanism for enhancing the thermodynamic stability of proteins. Generally it is observed that by enhancing the thermodynamic stability there is reduction in the rate of aggregation of proteins. Buffer (ligand) binds to the native state of the protein preferentially; it results in stabilization of the protein, while in the case of denatured protein it has no impact. There are many studies conducted involving the proteins in buffer solutions but very limited information is available about the mechanism of protein-buffer interactions. In the current study ligand binding mechanism of protein - buffer interaction was studied using molecular docking. After the docking buffers were ranked according to their energy value. The lower energy scores represent better protein-buffer (ligand) binding affinity compared to high energy values. It was observed that Phosphate with a binding affinity of -107.9 kcal/mol was the buffer with the least binding energy followed by Citrate (-70.6 kcal/mol), Melglumine (-66.6 kcal/mol), Arginine (-64.5 kcal/mol), Glucono delta lactone (-62.6 kcal/mol), Sodium citrate (-56.5 kcal/mol), Tromethamine (-52.3 kcal/mol), Glycine HCl (-37.2 kcal/mol), Sulfuric acid (-37.7 kcal/mol), Ammonium acetate (-31.1 kcal/mol), Acetic acid (-30.7 kcal/mol). With lower binding energy higher is the affinity between the ligand and protein. So phosphate was identified as a buffer with the highest affinity with Abatacept.

Unraveling heterogeneity within ACPA-negative rheumatoid arthritis: the subgroup of patients with a strong clinical and serological response to initiation of DMARD treatment favor disease resolution

BACKGROUND

Rheumatoid arthritis (RA) is a heterogeneous disease, as evidenced by the differences in long-term outcomes. This applies especially to anti-citrullinated protein antibodies (ACPA)-negative RA, where a proportion achieves sustained DMARD-free remission (SDFR; sustained absence of synovitis after DMARD cessation). Differentiation of RA patients who will achieve SDFR can guide personalized treatment/tapering strategies. Although this subgroup remains scarcely discerned, previous research demonstrated that these RA patients are characterized by an early clinical response (DAS remission after 4 months) after DMARD start. We studied whether, in addition to this clinical response, a specific biomarker response can further distinguish the subgroup of RA patients most likely to achieve SDFR.

METHODS

In 266 RA patients, levels of 12 biomarkers (SAA/CRP/MMP-1/MMP-3/resistin/leptin/IL-6/TNF-R1/YKL-40/EGF/VEGF/VCAM-1), in the first 2 years after diagnosis, were studied in relation to SDFR, stratified for ACPA status. Subsequently, biomarkers associated with SDFR development were combined with early DAS remission to study its additional value in defining subgroups. Since most biomarker levels are not routinely measured in clinical practice, we explored how this subgroup can be clinically recognized.

RESULTS

ACPA-negative RA patients achieving SDFR were characterized by high baseline levels and stronger decline in MMP-1/MMP-3/SAA/CRP after DMARD-start, respectively 1.30×/1.44×/2.12×/2.24× stronger. This effect was absent in ACPA-positive RA. In ACPA-negative RA, a strong biomarker decline is associated with early DAS remission. The combination of both declines (clinical, biomarker) was present in a subgroup of ACPA-negative RA patients achieving SDFR. This subgroup can be clinically recognized by the combination of high baseline CRP levels (≥ 3 times ULN), and early DAS remission (DAS_{4 months} < 1.6). This latter was replicated in independent ACPA-negative RA patients.

CONCLUSIONS

ACPA-negative RA patients with early DAS remission and a strong biomarker response (or baseline CRP levels ≥ 3× ULN) are most likely to achieve SDFR later on. This could guide personalized decisions on DMARD tapering/cessation in ACPA-negative RA.

Biomarker identification and pathway analysis of rheumatoid arthritis based on metabolomics in combination with ingenuity pathway analysis

Rheumatoid arthritis (RA) is a common autoimmune and inflammatory disease worldwide, but understanding its pathogenesis is still limited. In this study, plasma untargeted metabolomics of a discovery cohort and targeted analysis of a verification cohort were performed by gas chromatograph mass spectrometry (GC/MS). Univariate and multivariate statistical analysis were utilized to reveal differential metabolites, followed by the construction of biomarker panel through random forest (RF) algorithm. The pathways involved in RA were enriched by differential metabolites using Ingenuity Pathway Analysis (IPA) suite. Untargeted metabolomics revealed eighteen significantly altered metabolites in RA. Among these metabolites, a three-metabolite marker panel consisting of L-cysteine, citric acid and L-glutamine was constructed, using random forest algorithm that could predict RA with high accuracy, sensitivity and specificity based on a multivariate exploratory receiver operator characteristic (ROC) curve analysis. The panel was further validated by support vector machine (SVM) and partial least squares discriminant analysis (PLS-DA) algorithms, and also verified with targeted metabolomics using a verification cohort. Additionally, the dysregulated taurine biosynthesis pathway in RA was revealed by an integrated analysis of metabolomics and transcriptomics. Our findings in this study not only provided a mechanism underlying RA pathogenesis, but also offered alternative therapeutic targets for RA.

Decreased ALKBH5, FTO, and YTHDF2 in Peripheral Blood Are as Risk Factors for Rheumatoid Arthritis

ALKBH5 (alkylation repair homolog protein 5), FTO (fat mass and obesity-associated protein), and RNA N6-methyladenosine (m6A) demethylase, are essential for the m6A mRNA modification. YTHDF2 (YT521-B homology domains 2) called m6A “readers” can recognize m6A modification. As the key enzymes of m6A methylation modification, ALKBH5, FTO, and YTHDF2 have been implicated in many diseases. However, little is known about the role of ALKBH5, FTO, and YTHDF2 in rheumatoid arthritis (RA). We measured the mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients and controls by quantitative real-time polymerase chain reaction, and the global m6A content was detected by an ELISA-like format. The mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients was further analyzed to investigate its correlations with disease activity. And, multivariate analysis (logistic regression) was used to analyze the risk factors. The mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients was significantly decreased compared to controls. The mRNA expression of ALKBH5 was significantly increased in RA patients that received regular treatment. The mRNA expression of FTO was associated with disease activity score 28 (DAS28), complement 3 (C3), immunoglobulin G (IgG), and lymphocyte-to-monocyte ratio (LMR), some common markers for RA disease activity. The mRNA expression of YTHDF2 was associated with RBC, L%, N%, NLR, and LMR. Furthermore, logistic regression analysis revealed that decreased expression of ALKBH5, FTO, and YTHDF2 in peripheral blood was a risk factor for RA. Moreover, the peripheral blood global m6A content was significantly increased in patients with RA compared to CON, and increased m6A contents negatively correlated with decreased mRNA expression of FTO. In conclusion, this study firstly demonstrates the critical role of ALKBH5, FTO, and YTHDF2 in RA, which provides novel insights into recognizing the pathogenesis of RA and a promising biomarker for RA.

Macrophage migration inhibitory factor promoter polymorphisms are associated with disease activity in rheumatoid arthritis patients from Southern Mexico

Background

Macrophage migration inhibitory factor (MIF) is a cytokine capable of stimulating inflammatory cytokine and matrix metalloproteinase production from macrophages and synovial fibroblasts, which leads to persistent inflammation and bone degradation, two of the major pathological processes in rheumatoid arthritis (RA). The aim of this study was to evaluate the association of MIF promoter polymorphisms (−794CATT_5‐8rs5844572 and −173G > C, rs755622), circulating MIF levels, and mRNA expression with RA susceptibility and disease activity.

Methods

A case–control study was conducted in 200 RA patients and 200 control subjects (CS) from Southern Mexico. Genotyping was performed by conventional PCR and PCR‐RFLP methods. MIF mRNA expression was quantified by real‐time PCR and MIF serum levels were determined by an ELISA kit.

Results

The 7,7 (−794CATT_5‐8) and −173CC (−173G > C) genotypes were associated with higher disease activity in RA patients. MIF serum levels were increased, and MIF mRNA expression was reduced in RA patients as compared to CS. In addition, RA patients with moderate disease activity had higher MIF levels than those with low disease activity. The −794CATT_5‐8 and −173G > C MIF polymorphisms were not associated with RA susceptibility.

Conclusion

These results suggest an important role of MIF polymorphisms and MIF serum levels with disease activity in RA.

The expression of GAS5, THRIL, and RMRP lncRNAs is increased in T cells of patients with rheumatoid arthritis

OBJECTIVE

Long non-coding RNAs (lncRNAs) comprise a large and diverse group of non-coding RNAs (ncRNAs) with important regulatory roles in various biological processes, including the immune system regulation. Rheumatoid arthritis (RA) as an autoimmune disease initiates inflammation in the synovial joints. T cells infiltrating into the synovial membrane have an important role in the pathogenesis of RA. The aim of the current investigation was to analyze the expression of four lncRNAs in the T cells from RA patients and healthy controls.

METHODS

In the current study, we investigated the expression of GAS5, RMRP, IFNϒ-AS1, and THRIL lncRNAs in circulating T cells from 20 patients with RA and 18 healthy matched controls by quantitative real-time PCR. T cell isolation was accomplished using the MAC method. We also analyzed the correlation between lncRNA expression and clinical parameters. Also, the mRNA expression levels of IL-17 and TNF-α and the association between lncRNAs and these cytokines were examined.

RESULTS

The results indicate that T cells of RA patients display increased levels of GAS5 (3.31-fold, p = 0.007), RMRP (2.43-fold, p = 0.02), and THRIL (2.14-fold, p = 0.03) lncRNAs compared with those of controls. Furthermore, a positive correlation was found between RMRP expression and disease duration in RA. Receiver operating characteristic (ROC) curve of GAS5, RMRP, and THRIL has a discriminative value in comparing RA patients and controls.

CONCLUSION

The results suggest lncRNAs may be involved in T cell dysfunction in RA. Further studies are required to see whether these lncRNAs have an effect on dysregulation of immune responses in RA disease. Key Points • 70% of non-coding sequences in the human genome are transcribed to RNA. • A growing body of evidence shows the importance of lncRNAs in innate and adaptive immune cell differentiation and functions. • Important recent works suggest a key role of immune cell lncRNAs in autoimmune processes and diseases including RA.

Concurrent one-stage total knee and hip arthroplasty due to sequel of juvenile rheumatoid arthritis: A case report

RATIONALE

Rheumatoid arthritis is a chronic systemic connective tissue disease. Total hip and knee arthroplasties are common major orthopaedic procedures worldwide.

PATIENT CONCERNS

To date, no studies have presented 1-stage concurrent total hip arthroplasty (THA) and total knee arthroplasty (TKA) in patients with rheumatoid arthritis (RA). We reported a case which is, to our knowledge, the first description of both THA and TKA in a patient with RA simultaneously.

DIAGNOSES

History of juvenile rheumatoid arthritis (JRA), deterioration of signs and symptoms in history and physical examinations and radiography were lead to making decision for her surgery.

INTERVENTIONS

Concurrent total hip replacement and total knee arthroplasty were performed for patient.

OUTCOMES

After more than a 2-year follow-up time, the patient showed excellent clinical function and remained satisfied with the surgical outcome. Multiple simultaneous total joint arthroplasty (TJA) is reviewed in this article.

LESSONS

Joint arthroplasty surgeries can be performed in a simultaneous procedure to shorten disability and rehabilitation time with one anesthesia.

Transglutaminase 2 in cartilage homoeostasis: novel links with inflammatory osteoarthritis

Transglutaminase 2 (TG2) is highly expressed during chondrocyte maturation and contributes to the formation of a mineralised scaffold by introducing crosslinks between extracellular matrix (ECM) proteins. In healthy cartilage, TG2 stabilises integrity of ECM and likely influences cartilage stiffness and mechanistic properties. At the same time, the abnormal accumulation of TG2 in the ECM promotes chondrocyte hypertrophy and cartilage calcification, which might be an important aspect of osteoarthritis (OA) initiation. Although excessive joint loading and injuries are one of the main causes leading to OA development, it is now being recognised that the presence of inflammatory mediators accelerates OA progression. Inflammatory signalling is known to stimulate the extracellular TG2 activity in cartilage and promote TG2-catalysed crosslinking of molecules that promote chondrocyte osteoarthritic differentiation. It is, however, unclear whether TG2 activity aims to resolve or aggravate damages within the arthritic joint. Better understanding of the complex signalling pathways linking inflammation with TG2 activities is needed to identify the role of TG2 in OA and to define possible avenues for therapeutic interventions.

The functional variants of endothelial nitric oxide synthase gene associated with rheumatoid arthritis in Turkish adults

This study aimed to investigate whether functional variants of endothelial nitric oxide synthase (eNOS) gene play any role in rheumatoid arthritis (RA) ethiopathogenesis and treatment in the Turkish population. Because, eNOS variants are responsible for alteration of the NO level in plasma, by reducing/increasing the endothelial NO synthesis. In the study, two eNOS gene variants (G894T and intron 4 VNTR A/B) were examined at extracted DNAs from 65 peripheral blood cell of RA patients. For the control, blood samples obtained from 70 healthy persons were studied. Genotyping of molecular variants was performed by PCR-RFLP and/or PCR technique. The data obtained was compared in itself and response to therapy. We found that "TT genotypic frequency" for the G894T variant was significantly associated with RA with an overall risk of 8.3-fold (p 0.029). No association was identified between intron 4 VNTR A/B variant and RA. At the 6 months, the mean visual analog scale (VAS), health assessment questionnaire (HAQ), and disease activity score for 28 joints (DAS 28) improvement was not significant among groups. Improvement in DAS was significantly better in anti-TNF treatment than disease-modifying antirheumatic drugs (DMARD) treatment treated subgroup. We report for the first time that variants in the eNOS "TT" genotype might be contributed to the increased risk of RA in the Turkish population. These results imply that functional variants of eNOS gene might have an effect on RA patients and response to anti-TNF treatment. In addition, the results suggest that eNOS variants might be associated and affect host susceptibility and/or response to treatment in Turkish RA patients.

APL-1, an altered peptide ligand derived from heat-shock protein, alone or combined with methotrexate attenuates murine collagen-induced arthritis

Induction of tolerance to autoantigens in vivo is a complex process that involves several mechanisms such as the induction of regulatory T cells and changes in the cytokine and chemokine profiles. This approach represents an attractive alternative for treatment of autoimmune diseases. APL-1 is an altered peptide ligand derived from a novel CD4 + T cell epitope of human heat-shock protein of 60 kDa (HSP60), an autoantigen involved in the pathogenesis of rheumatoid arthritis (RA). We have shown previously that this peptide efficiently inhibited the course of adjuvant-induced arthritis in Lewis rats and induced regulatory T cell (Treg) in ex vivo assay with PBMC isolated from RA patients. This study was undertaken to evaluate the therapeutic effect of APL-1 and its combination with methotrexate (MTX) in collagen-induced arthritis (CIA). CIA was induced in male DBA/1 mice at 8 weeks of age by immunization with chicken collagen. APL, MTX or both were administrated beginning from arthritis onset. Therapeutic effect was evaluated by arthritis and joint pathologic scores. In addition, TNFα and IL-10 in sera were measured by ELISA. Treg induction was assessed by FACS analysis. APL-1 inhibits efficiently the course of arthritis in CIA, similar to MTX. In addition, therapy with APL-1 plus MTX reduced CIA in mice, associated with an increase in Treg. These facts reinforce the therapeutic possibilities of APL-1 as a candidate drug for treatment of RA.

The Risk of Tuberculosis in Patients with Rheumatoid Arthritis Treated with Tumor Necrosis Factor-α Antagonist: A Metaanalysis of Both Randomized Controlled Trials and Registry/Cohort Studies

OBJECTIVE

Tumor necrosis factor-α (TNF-α) antagonists have significantly improved treatment results in rheumatoid arthritis (RA), but have also increased the risk of tuberculosis (TB). Etanercept (ETN), adalimumab (ADA), infliximab (IFX), golimumab, and certolizumab pegol are the 5 drugs currently available on the market. This article aimed to evaluate the risk of TB infection from these 5 drugs for patients with RA.

METHODS

We searched PubMed, EMBASE, COCHRANE library, OVID, and EBSCO for randomized controlled trials (RCT) of TNF-α antagonist versus control and registry/longitudinal cohort studies of 1 TNF-α antagonist versus another. The Mantel-Haenszel test was adopted to analyze risk ratio (RR) in this metaanalysis.

RESULTS

Fifty RCT and 13 non-RCT were included in this study. No significant difference in TB risk was found in the RCT because of the short observational periods. In the non-RCT, TNF-α antagonist was associated with a higher TB risk in patients with RA (RR 4.03, 95% CI 2.36-6.88), and the TB incidence rates of IFX and ADA were 2.78 and 3.88 times, respectively, higher than that of ETN. Further, preventive treatment for latent TB infection (LTBI) was shown to reduce the TB risk by 65% (RR 0.35, 95% CI 0.15-0.82).

CONCLUSION

This study demonstrated a significant increase in TB risk in patients with RA treated with TNF-α antagonists; among them, ETN is least likely to cause active TB. The study also proposes the necessity of LTBI prophylaxis in patients with RA.

Expression of co-stimulatory molecule B7-H4 in patients suffering from rheumatoid arthritis

B7-H4, an inhibitory modulator of T-cell response, is one of the most recently identified cell surface molecules in the B7-CD28 signaling pathway. However, its role in the pathogenesis of rheumatoid arthritis (RA) remains unclear. In the present study, the immunofluorescence staining, confocal laser scanning microscopy and flow cytometry techniques were used to characterize B7-H4 protein expression in RA synovium tissues and peripheral blood mononuclear cell (PBMC) subsets, respectively. Our data showed that the immunolocalization of B7-H4 could be found on the membrane and in the cytoplasm of synoviocytes and CD19(+) B cells in rheumatoid synovium tissues, while B7-H4 was weakly or negatively expressed on CD3(+) T cells, CD14(+) monocytes and CD68(+) macrophages. Moreover, B7-H4 expression was observed in CD34(+) endothelial cells of neovessels in rheumatoid synovium. Flow cytometric analysis also showed that positive B7-H4 expression was found in CD19(+) B cells and CD14(+) monocytes, but not in CD3(+) T cells. Thus, our work identified the expression pattern of B7-H4 in the synovium tissues and PBMC subsets from RA patients, suggesting that B7-H4 involves in the pathological changes of rheumatoid synovium in RA progression, and its detailed biological function needs further investigations.

Ankylosing spondylitis: from cells to genes

Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown etiology, though it is considered an autoimmune disease. HLA-B27 is the risk factor most often associated with AS, and although the mechanism of involvement is unclear, the subtypes and other features of the relationship between HLA-B27 and AS have been studied for years. Additionally, the key role of IL-17 and Th17 cells in autoimmunity and inflammation suggests that the latter and the cytokines involved in their generation could play a role in the pathogenesis of this disease. Recent studies have described the sources of IL-17 and IL-23, as well as the characterization of Th17 cells in autoimmune diseases. Other cells, such as NK and regulatory T cells, have been implicated in autoimmunity and have been evaluated to ascertain their possible role in AS. Moreover, several polymorphisms, mutations and deletions in the regulatory proteins, protein-coding regions, and promoter regions of different genes involved in immune responses have been discovered and evaluated for possible genetic linkages to AS. In this review, we analyze the features of HLA-B27 and the suggested mechanisms of its involvement in AS while also focusing on the characterization of the immune response and the identification of genes associated with AS.

Serum matrix metalloproteinase-3 in comparison with acute phase proteins as a marker of disease activity and radiographic damage in early rheumatoid arthritis

Matrix metalloproteinase-3 (MMP-3) is involved in the immunopathogenesis of rheumatoid arthritis (RA), but little is known about its relationship to genetic susceptibility and biomarkers of disease activity, especially acute phase reactants in early RA. MMP-3 was measured by ELISA in serum samples of 128 disease-modifying, drug-naïve patients and analysed in relation to shared epitope genotype, a range of circulating chemokines/cytokines, acute phase reactants, autoantibodies, cartilage oligomeric protein (COMP), and the simplified disease activity index (SDAI). MMP-3 was elevated >1.86 ng/ml in 56.25% of patients (P < 0.0001), correlated with several biomarkers, notably IL-8, IL-6, IFN γ , VEGF and COMP (r values = 0.22-0.33, P < 0.014-0.0001) and with CRP and SAA levels (r = 0.40 and 0.41, resp., P < 0.0000) and SDAI (r = 0.29, P < 0.0001), but not with erosions or nodulosis. However, the correlations of CRP and SAA with SDAI were stronger (respective values of 0.63 and 0.54, P < 0.001 for both). COMP correlated with smoking, RF, and MMP-3. MMP-3 is significantly associated with disease activity, inflammatory mediators and cartilage breakdown, making it a potential biomarker of disease severity, but seemingly less useful than CRP and SAA as a biomarker of disease activity in early RA.

A systematic review and meta-analysis comparing complications following total joint arthroplasty for rheumatoid arthritis versus for osteoarthritis

OBJECTIVE

Most of the evidence regarding complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA) is based on studies of patients with osteoarthritis (OA), with little being known about outcomes in patients with rheumatoid arthritis (RA). The objective of the present study was to review the current evidence regarding rates of THA/TKA complications in RA versus OA.

METHODS

Data sources used were Medline, EMBase, Cinahl, Web of Science, and reference lists of articles. We included reports published between 1990 and 2011 that described studies of primary total joint arthroplasty of the hip or knee and contained information on outcomes in ≥200 RA and OA joints. Outcomes of interest included revision, hip dislocation, infection, 90-day mortality, and venous thromboembolic events. Two reviewers independently assessed each study for quality and extracted data. Where appropriate, meta-analysis was performed; if this was not possible, the level of evidence was assessed qualitatively.

RESULTS

Forty studies were included in this review. The results indicated that patients with RA are at increased risk of dislocation following THA (adjusted odds ratio 2.16 [95% confidence interval 1.52-3.07]). There was fair evidence to support the notion that risk of infection and risk of early revision following TKA are increased in RA versus OA. There was no evidence of any differences in rates of revision at later time points, 90-day mortality, or rates of venous thromboembolic events following THA or TKA in patients with RA versus OA. RA was explicitly defined in only 3 studies (7.5%), and only 11 studies (27.5%) included adjustment for covariates (e.g., age, sex, and comorbidity).

CONCLUSION

The findings of this literature review and meta-analysis indicate that, compared to patients with OA, patients with RA are at higher risk of dislocation following THA and higher risk of infection following TKA.

Fibrates as therapy for osteoarthritis and rheumatoid arthritis? A systematic review

Fibrates are used as lipid-lowering drugs to prevent cardiovascular pathology. Fibrates are ligands of peroxisome proliferator-activated receptor α (PPARα). Besides altering lipid metabolism, PPARα ligands exert anti-inflammatory effects on various cell types. In this study, we hypothesized that PPARα agonists exert beneficial effects on osteoarthritis (OA) and rheumatoid arthritis (RA) by their local anti-inflammatory effects, but also by their systemic influences. A systematic literature search of Medline and EMBASE databases was performed up to August 2011. The main search items were osteoarthritis, rheumatoid arthritis, peroxisome proliferator-activated receptor alpha and fibrates. Inclusion criteria were in vivo or in vitro studies regarding humans or animals in which the effects of PPARα ligands were studied. Six in vivo human studies, four in vivo animal studies and seven in vitro studies were included. The in vivo human studies showed all beneficial clinical effects of PPARα ligands, but studies were small and only four were randomized. Ligands for PPARα significantly reduced pain, swelling of the joints and decreased systemic inflammatory markers. In vitro and in vivo animal studies indicate that PPARα agonists inhibit bone resorption, and reduce inflammatory and destructive responses in cartilage and synovium. PPARα agonists such as fibrates should be considered as potential therapeutic strategy for RA. There is no clinical evidence for their use in OA, although in vitro studies indicate that PPARα agonists demonstrate different joint-protective effects locally, and systemic effects on inflammation, serum lipid levels and vascular pathology. Animal studies should be performed and after confirmation of the protective effects of PPARα, large randomized controlled trials could investigate fibrates in OA and RA.

What is causing my arthritis, doctor? A glimpse beyond the usual suspects in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common, but heterogeneous, disease. Usually, when it comes to the pathogenesis of RA the physician faces a complex network of cytokines and cells of the immune system-the so-called effector level. However, is this network 'the cause' of the disease? Or is this rather the level most physicians are somewhat familiar with, as modern anti-rheumatic medications are having their targets there? In this review, we are looking beyond the usual culprits from the physician's perspective and discuss how other factors, such as genes, epigenetics, environmental factors, local joint characteristics or processes of aging might influence the clinical phenomenon RA.

Macrophage migration inhibitory factor (MIF): genetic evidence for participation in early onset and early stage rheumatoid arthritis

Macrophage migration inhibitory factor (MIF) is an upstream pro-inflammatory cytokine that is associated with the pathogenesis of autoimmune inflammatory diseases including rheumatoid arthritis (RA). Two polymorphisms in the upstream region exist in the MIF gene and are associated with RA susceptibility or severity in different populations. In this case-control study, we investigated whether MIF polymorphisms are associated with RA susceptibility or activity in a western Mexican population .The relationship of MIF levels with clinical features of disease also was assessed. Genotyping of the -794 CATT5-8 (rs5844572) and the -173 G>C (rs755622) polymorphisms was performed by PCR and PCR-RFLP respectively on 226 RA patients and 210 healthy subjects. Serum MIF levels were determined by ELISA. We found a significant association between the -794 CATT5-8 6,7 MIF genotype with RA. Moreover, we detected an association between the -794 CATT7 allele with early onset RA. The -794 CATT7 and -173(*)C alleles, which are in linkage disequilibrium, were associated with high disease activity on RA patients. A positive correlation between circulating MIF levels and C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, anti-citrullinated protein/peptides antibodies and TNFα was detected. MIF levels appear to be associated with disease progression rather than disease activity, which is distinct from the established relationship between disease activity and TNFα levels. In conclusion, the MIF gene and protein are associated with RA in a western Mexican population, with a main contribution onto early onset and early stages of disease.

Microarray-based gene expression profiling reveals the mediators and pathways involved in the anti-arthritic activity of Celastrus-derived Celastrol

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the joints. The prolonged use of non-steroidal anti-inflammatory drugs and other newer drugs is associated with severe adverse reactions. Therefore, there is a need for newer anti-arthritic agents. Celastrol, a bioactive component of the Chinese herb Celastrus, possesses anti-arthritic activity as tested in the adjuvant arthritis (AA) model of rheumatoid arthritis (RA). However, the mechanism of action of Celastrol has not been fully defined. We reasoned that microarray analysis of the lymphoid cells of Celastrol-treated arthritic animals might provide vital clues in this regard. We isolated total RNA of the draining lymph node cells (LNCs) of Celastrol-treated (Tc) and vehicle-treated (Tp) arthritic Lewis rats that were restimulated in vitro with the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65), and tested it using microarray gene chips. Also tested was RNA from LNCs of control arthritic rats just before any treatment (T₀). Seventy six genes involved in various biological functions were differentially regulated by Bhsp65 in LNCs of Tp group, and 19 genes among them were shared by the Tc group. Furthermore, a group of 14 genes was unique to Tc. When Tc and Tp were compared, many of the Bhsp65-induced genes were related to the immune cells, cellular proliferation and inflammatory responses. Our results revealed 10 differentially expressed genes and 14 pathways that constituted the "Celastrol Signature". Our results would help identify novel targets for RA therapy.

Therapeutic effect of an altered peptide ligand derived from heat-shock protein 60 by suppressing of inflammatory cytokines secretion in two animal models of rheumatoid arthritis

Rheumatoid arthritis is a systemic autoimmune disease mediated by T cells. Productive engagement of T cell receptors by major histocompatibility complex-peptide leads to proliferation, differentiation and the definition of effector functions. Altered peptide ligands (APL) generated by amino acid substitutions in the antigenic peptide have diverse effects on T cell response. We predicted a novel T cell epitope from human heat-shock protein 60, an autoantigen involved in the pathogenesis of rheumatoid arthritis. Three APLs were designed from this epitope and it was demonstrated that these peptides induce the activation of T cells through their ability to modify cell cycle phase's distribution of CD4+T cells from RA patients. Also, IL-17, TNF-α and IL-10 levels were determined in PBMC from these patients. Unlike the wild-type peptide and the other two APLs, APL2 increased the IL-10 level and suppressed IL-17 secretion in these assays. Therapeutic effect of this APL in adjuvant arthritis (AA) and collagen-induced arthritis (CIA) models was also evaluated. Clinical score, histopathology, inflammatory and regulatory cytokine concentration were monitored in the animals. APL2 efficiently inhibited the progression of AA and CIA with a significant reduction of the clinical and histopathologic score. Therapeutic effect of APL2 on CIA was similar to that obtained with MTX; the standard treatment for RA. This effect was associated with a decrease of TNF-α and IL-17 levels. These results suggest that the therapeutic effect of APL2 is mediated in part by down-regulation of inflammatory cytokines and support the potential use of APL2 as a therapeutic drug in RA patients.

RANTES, MCP-1 chemokines and factors describing rheumatoid arthritis

The MCP-1/CCL2 as well as RANTES/CCL5 chemokines are potent chemoattractants involved in immunoregulatory and inflammatory processes of rheumatoid arthritis. Recent studies demonstrated elevated levels of MCP-1 and RANTES in plasma, synovial fluid, and the synovial tissue of patients with RA. To examine the relationship among MCP-1 and RANTES single nucleotide polymorphisms and circulating levels and rheumatoid arthritis (RA), a total of 156 RA patients and 125 controls were recruited into the study. An association of -855 C/G MCP-1 polymorphism to IgM RF within the RA patients was observed. The lowest circulating levels of RANTES were observed in the AA variant of RANTES -403 G/A polymorphism. Furthermore, an association of -403 AA variant to circulating levels of IL-15 and IL-10 was found. No associations of factors describing rheumatoid arthritis (RFs, ANA, anti-CCP-positive/negative, DAS 28 score and number of swollen joints) with MCP-1 levels, genotype distribution, allelic frequencies and/or frequencies of haplotypes composed of all three studied polymorphisms in promoter region of MCP-1, and RANTES polymorphism were observed. We conclude that the RANTES promoter polymorphism is associated to circulating levels of RANTES, IL15 and IL10. However, our findings suggest that polymorphisms in the MCP-1 and RANTES gene promoters do not contribute significantly to the interindividual RA susceptibility and/or severity in Caucasians.

HLA-DRB1 shared epitope genotyping using the revised classification and its association with circulating autoantibodies, acute phase reactants, cytokines and clinical indices of disease activity in a cohort of South African rheumatoid arthritis patients

Introduction

The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).

Methods

Genomic DNA was analysed using high-resolution recombinant sequence-specific oligonucleotide PCR typing of the HLA-DRB1 allele. Subtypes of the SE were classified according to the amino acids at positions 72 to 74 for the RAA sequence, and further sub-divided according to the amino acids at positions 70 and 71, which either contribute to (S2, S3P), or negate (S1, S3D) RA susceptibility. Disease activity was assessed on the basis of (1) Disease Activity Score in 28 joints using C-reactive protein (CRP), (2) rheumatoid factor (RF), (3) CRP and (4) serum amyloid A by nephelometry, anticyclic citrullinated peptide antibodies (aCCP) by an immunofluorometric procedure, and cytokines by multiplex bead array technology.

Results

Of the 143 RA patients, 81 (57%) were homozygous (SS) and 50 (35%) were heterozygous (SX) for the SE alleles with significant overexpression of S2 and S3P (respective odds ratios (ORs) 5.3 and 5.8; P < 0.0001), and 12 (8%) were classified as no SE allele (XX). Both the SS and SX groups showed a strong association with aCCP positivity (OR = 10.2 and P = 0.0010, OR = 9.2 and P = 0.0028, respectively) relative to the XX group. Clinical scores and concentrations of the other biomarkers of disease activity (RF, CRP and T helper cell type 1 (Th1), Th2, macrophage and fibroblast cytokines) were also generally higher in the SS group than in the SX and XX groups.

Conclusions

RA susceptibility alleles investigated according to revised criteria for the classification of RA were significantly increased in South African RA patients and strongly associated with aCCP in particular as well as with circulating cytokines and disease severity.

Cannabinoids as novel anti-inflammatory drugs

Cannabinoids are a group of compounds that mediate their effects through cannabinoid receptors. The discovery of Δ9-tetrahydrocannabinol (THC) as the major psychoactive principle in marijuana, as well as the identification of cannabinoid receptors and their endogenous ligands, has led to a significant growth in research aimed at understanding the physiological functions of cannabinoids. Cannabinoid receptors include CB1, which is predominantly expressed in the brain, and CB2, which is primarily found on the cells of the immune system. The fact that both CB1 and CB2 receptors have been found on immune cells suggests that cannabinoids play an important role in the regulation of the immune system. Recent studies demonstrated that administration of THC into mice triggered marked apoptosis in T cells and dendritic cells, resulting in immunosuppression. In addition, several studies showed that cannabinoids downregulate cytokine and chemokine production and, in some models, upregulate T-regulatory cells (Tregs) as a mechanism to suppress inflammatory responses. The endocannabinoid system is also involved in immunoregulation. For example, administration of endocannabinoids or use of inhibitors of enzymes that break down the endocannabinoids, led to immunosuppression and recovery from immune-mediated injury to organs such as the liver. Manipulation of endocannabinoids and/or use of exogenous cannabinoids in vivo can constitute a potent treatment modality against inflammatory disorders. This review will focus on the potential use of cannabinoids as a new class of anti-inflammatory agents against a number of inflammatory and autoimmune diseases that are primarily triggered by activated T cells or other cellular immune components.

Methotrexate ameliorates pristane-induced arthritis by decreasing IFN-γ and IL-17A expressions

OBJECTIVE

This study was carried out to test the effects of methotrexate (MTX) and black seed oil (BSO) on pristane-induced arthritis (PIA) in rats.

METHODS

Inbred dark agouti (DA) rats were induced by a single subcutaneous injection of pristane, and then treated with MTX or BSO. Arthritis severity was evaluated macroscopically and microscopically. Plasma nitric oxide (NO) concentration was determined by the Griess method and cytokine mRNA expression in the spleen was detected by the real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The clinical arthritis severity was decreased after MTX treatment, while the BSO groups did not show significant changes compared with the disease group. The plasma NO level of the MTX group was significantly decreased compared with the disease group, but the BSO groups showed no difference from the disease group in plasma NO levels. The interferon-γ (IFN-γ) and interleukin-17A (IL-17A) mRNA expressions in the spleens were significantly decreased in the MTX group, but only showed a declining trend in the BSO groups compared with the disease group. Neither MTX nor BSO had an effect on the mRNA expressions of IL-4, transforming growth factor β (TGF-β), and tumor necrosis factor-α (TNF-α) in the spleen.

CONCLUSIONS

MTX, but not BSO, can reduce the arthritis severity and decrease the mRNA expressions of IFN-γ and IL-17A in pristane-induced arthritis of rats.

Interaction between oxidative stress and chemokines: possible pathogenic role in systemic lupus erythematosus and rheumatoid arthritis

Imbalance oxidative stress and chemokines are considered as a universal factors involved in the development of various clinical features seen in the patients with SLE and arthritis. To evaluate the interaction between oxidative stress and chemokines and their relationship with disease activity in SLE and RA patients, oxidative/anti-oxidant profiles and chemokines were assessed. Oxidant and anti-oxidant enzymes were measured in the plasma and the levels of chemokines; MCP-1/CCL2, RANTES/CCL5, MIP-1β/CCL-4 and IP-10/CXCL-10 were evaluated in the serum by an enzyme-linked immunosorbent assay (ELISA). A significant increase in the level of lipid peroxidation was found in SLE and RA patients and positively associated with disease activity. The activities of anti-oxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and anti-oxidant molecule GSH were significantly reduced in both diseases. Strong positive associations were found between MDA with RANTES/CCL5 and MIP-1β/CCL4 than MCP-1/CCL-2 in SLE patients while a sturdy connotation was seen with MIP-1β/CCL4 and MCP-1/CCL-2 in RA patients. The anti-oxidant molecule GSH shows a negative association with serum levels of MCP-1/CCL-2, RANTES/CCL5 and IP-10/CXCL-10 in SLE patients and with MCP-1/CCL-2 and RANTES/CCL5 in RA patients. A low level of GSH and high level of RANTES/CCL5 were associated with lupus nephritis patients. These results indicates that excessive production of ROS disturbs redox status and can modulate the expression of inflammatory chemokines leading to inflammatory processes, exacerbating inflammation and affecting tissue damage in autoimmune diseases, as exemplified by their strong association with disease activity.

The value of rheumatoid factor and anti-citrullinated protein antibodies as predictors of response to infliximab in rheumatoid arthritis: an exploratory study

OBJECTIVE

It remains unclear whether autoantibodies are useful biomarkers to tailor the choice of biological treatment in RA. We investigated the relationship between the presence and levels of different RF and ACPA isotypes and the response to TNF blockade in an exploratory study.

METHODS

A total of 101 active RA patients were prospectively treated with infliximab (3 mg/kg). Changes in disease activity were monitored by the 28-joint DAS (DAS-28). Serum levels of different isotypes [immunoglobulins M, G and A (IgM, IgG and IgA)] of RF and anti-citrullinated peptide antibodies were measured by ELISA.

RESULTS

The mean DAS-28 decreased from 5.9 (1.1) at baseline to 4.0 (1.3) at Week 16 of infliximab treatment (P < 0.001). High baseline levels of different isotypes of RF (all P < 0.008), ACPA IgM (P = 0.008) and ACPA IgG (P = 0.07) were associated with an absolute decrease in DAS-28 after TNF blockade. This relationship persisted after adjusting for DAS-28 at baseline. However, the different isotypes of baseline RF and ACPA levels accounted for only a small proportion of variance in treatment response (RF: R² between 7 and 12% and ACPA: R² between 4 and 7%). The simultaneous presence of all three isotypes of RF or ACPA had no additive value.

CONCLUSION

Presence as well as the titres of RF and IgM ACPA at baseline are significantly correlated with better response to infliximab treatment. However, this correlation is not strong enough to allow a reliable prediction in individual patients. Trial Registration. ISRCTN Register, http://www.controlled-trials.com/isrctn/, ISRCTN36847425.

New therapeutic options in rheumatoid arthritis: a focus on interleukin-6 blockade

Rheumatoid arthritis (RA), a chronic and incurable autoimmune disease characterized by synovial joint damage and systemic inflammation, often leads to substantial disability and reduced quality of life. Biologics, a class of medication that targets key pathways in the RA inflammatory response, have increased therapeutic options in the past decade. Because several biologics are administered intravenously, specialized training in administration and updates on RA management are increasingly needed. This article reviews the pathogenesis of RA and the biologics newly approved by the US Food and Drug Administration, such as the interleukin-6 inhibitor tocilizumab, including their targets in the inflammatory cascade.

HLA-DRB1 allele distribution and its relation to rheumatoid arthritis in eastern Black Sea Turkish population

Rheumatoid arthritis (RA [MIM 180300]) is a complex, polygenic inflammatory autoimmune disease, resulting from interactions between genetic and environmental factors. Some of the RA-associated HLA-DRB1 alleles have shared epitope, but their distribution varies among different racial/ethnic groups. This study was aimed at investigating the distribution of HLA-DRB1 alleles in patients with RA in eastern Black Sea region of Turkey. DNA samples of 320 patients with RA and 360 healthy controls were studied for the determination of HLA-DRB1 allele distribution using PCR-SSP method. The allele frequencies of HLA-DRB1*01, *04, and *09 were higher in patients with RA compared with the controls (P < 0.005, P < 0.0001, and P < 0.01, respectively). On the other hand, in patients with RA, HLA-DRB1*13 allele was lower than the controls (P < 0.001). Of the HLA-DRB1*04 subgroups, *0401 (40.83% vs. 18.75%, P < 0.001) was the most frequent allele in patients with RA, while DRB1*0402 (30.00% vs. 12.50%, P < 0.005) allele in the controls. HLA-DRB1 allele frequencies in the patients with RA and the controls showed Hardy-Weinberg rule compliance. Results of this study indicate that HLA-DRB1*01, *04, and *09 alleles were associated with RA, and HLA-DRB1*13 was protective allele against RA. Among the subgroups of HLA-DRB1*04, *0401 was detected to be RA associated, while *0402 was being protective. These results have some differences compared with previous reports originating from other regions of Turkey.

Proteome analysis of biological fluids from autoimmune-rheumatological disorders

Autoimmune-rheumatological diseases are worldwide distributed disorders and represent a complex array of illnesses characterized by autoreactivity (reactivity against self-antigens) of T-B lymphocytes and by the synthesis of autoantibodies crucial for diagnosis (biomarkers). Yet, the effects of the autoimmune chronic inflammation on the infiltrated tissues and organs generally lead to profound tissue and organ damage with loss of function (i.e., lung, kidney, joints, exocrine glands). Although progresses have been made on the knowledge of these disorders, much still remains to be investigated on their pathogenesis and identification of new biomarkers useful in clinical practice. The rationale of using proteomics in autoimmune-rheumatological diseases has been the unmet need to collect, from biological fluids that are easily obtainable, a summary of the final biochemical events that represent the effects of the interplay between immune cells, mesenchymal cells and endothelial cells. Proteomic analysis of these fluids shows encouraging results and in this review, we addressed four major autoimmune-rheumatological diseases investigated through proteomic techniques and provide evidence-based data on the highlights obtained in systemic sclerosis, primary and secondary Sjogren's syndrome, systemic lupus erythematosus and rheumatoid arthritis.

Plant-made pharmaceuticals for the prevention and treatment of autoimmune diseases: where are we?

Molecular farming in plants or plant cell cultures represents a viable alternative technology that holds great promise for the low-cost and large-scale production of recombinant proteins. The particular case of plant-based vaccines for the prevention of autoimmune diseases is addressed here, presenting a comprehensive overview of the different molecules and expression technologies that have been investigated so far in both academia and industry. The potential of plants not only as bioreactors but also as delivery systems for pharmaceuticals is discussed, and the advantages of oral delivery of autoantigens for the induction of immune tolerance are highlighted.

The changing face of rheumatoid arthritis: sustained remission for all?

Earlier diagnosis and treatment, plus biological therapies, have transformed the outlook for many patients with rheumatoid arthritis. In the future, new biomarkers for diagnosis, prognosis and therapeutic response will further improve outcomes. Additionally, preclinical diagnosis and tolerogenic therapies could provide sustained remission for some individuals, although ethical and societal challenges must also be addressed before rheumatoid arthritis becomes 'yesterday's disease'.

Purified proteins from Leishmania amastigotes-induced delayed type hypersensitivity reactions and remission of collagen-induced arthritis in animal models

A treatment preparation composed of purified Leishmania (L) antigenic fractions (AS210) induced linear delayed type hypersensitivity (DTH) reactions over a 1-40 microg dose range, in guinea pigs. When a DBA-1 mouse collagen induced arthritis (CIA) model was used to compare AS210 treatment against: a polyvalent vaccine (AS110-1), a monovalent vaccine (AS110-2) and placebo, the AS210 treated mice had the least amount of forepaw inflammation and the lowest mean arthritis scores (MAS). When MAS for day(s) 1-40 were analyzed using one way ANOVA, statistically significant (P < 0.05) differences were seen for the following study groups: PBS versus Dexamethasone and PBS versus AS210. Subsequently, the ANOVA analysis results were corroborated by the Mann-Whitney test: analysis of the first group (P < 0.001) and analysis of the second group (P < 0.001). Comparison between dexamethasone and AS210 at different time intervals by Mann-Whitney test were as follows: day 0-day 5 both treatments had equal values (P = 1.00), from day-7 to 20 AS210 treatment had lower MAS values than dexamethasone (P = 0.037), and from day-21 to 30, AS210 MAS were similar to dexamethasone values (P = 0.319). No statistical difference was observed between AS110-1, AS110-2, and placebo groups.

Natural killer cells in human autoimmunity

Natural killer (NK) cells are innate immune cells. Although NK cells are best characterized for their ability to control tumors and infections, recent data have indicated that they also are important regulatory cells by virtue of interactions with many types of immune and nonimmune cells. Thereby, they can affect the outcome of adaptive immune responses and maintain immune homeostasis. Thus, NK cells can either exacerbate or limit immune responses, including those to autoantigens. Here, we discuss current insights into the role of NK cells in human autoimmunity.