Neutrophil extracellular traps in rheumatoid arthritis and periodontitis: Contribution of PADI4 gene polymorphisms

AIM

We sought to investigate the release of neutrophil extracellular traps (NETs) in neutrophils from individuals with rheumatoid arthritis (RA) and controls and compare the presence of NETs in gingival tissues according to periodontal status. Also, the association between single nucleotide polymorphisms (SNPs) of the peptidyl arginine deaminase type 4 (PADI4) gene and the GTG haplotype with RA, periodontitis and NETs was evaluated in vitro.

MATERIALS AND METHODS

Peripheral neutrophils were isolated by density gradient, and NET concentration was determined by the PicoGreen method. Immunofluorescence was studied to identify NETs by co-localization of myeloperoxidase (MPO)-citrullinated histone H3 (H3Cit). Genotyping for SNPs (PADI4_89; PADI4_90; PADI4_92; and PADI4_104) was performed in 87 individuals with RA and 111 controls.

RESULTS

The release of NETs in vitro was significantly higher in individuals with RA and periodontitis and when stimulated with Porphyromonas gingivalis. Gingival tissues from subjects with RA and periodontitis revealed increased numbers of MPO-H3Cit-positive cells. Individuals with the GTG haplotype showed a higher release of NETs in vitro and worse periodontal parameters.

CONCLUSIONS

The release of NETs by circulating neutrophils is associated with RA and periodontitis and is influenced by the presence of the GTG haplotype.

Neutrophil extracellular traps mediate bone erosion in rheumatoid arthritis by enhancing RANKL-induced osteoclastogenesis

BACKGROUND AND PURPOSE

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can cause bone erosion due to increased osteoclastogenesis. Neutrophils involvement in osteoclastogenesis remains uncertain. Given that neutrophil extracellular traps (NETs) can act as inflammatory mediators in rheumatoid arthritis, we investigated the role of NETs in stimulating bone loss by potentiating osteoclastogenesis during arthritis.

EXPERIMENTAL APPROACH

The level of NETs in synovial fluid from arthritis patients was assessed. Bone loss was evaluated by histology and micro-CT in antigen-induced arthritis (AIA)-induced WT mice treated with DNase or in Padi4-deficient mice (Padi4flox/flox LysMCRE ). The size and function of osteoclasts and the levels of RANKL and osteoprotegerin (OPG) released by osteoblasts that were incubated with NETs were measured. The expression of osteoclastogenic marker genes and protein levels were evaluated by qPCR and western blotting. To assess the participation of TLR4 and TLR9 in osteoclastogenesis, cells from Tlr4-/- and Tlr9-/- mice were cultured with NETs.

KEY RESULTS

Rheumatoid arthritis patients had higher levels of NETs in synovial fluid than osteoarthritis patients, which correlated with increased levels of RANKL/OPG. Moreover, patients with bone erosion had higher levels of NETs. Inhibiting NETs with DNase or Padi4 deletion alleviated bone loss in arthritic mice. Consistently, NETs enhanced RANKL-induced osteoclastogenesis that was dependent on TLR4 and TLR9 and increased osteoclast resorptive functions in vitro. In addition, NETs stimulated the release of RANKL and inhibited osteoprotegerin in osteoblasts, favouring osteoclastogenesis.

CONCLUSIONS AND IMPLICATIONS

Inhibiting NETs could be an alternative strategy to reduce bone erosion in arthritis patients.

Measurement of Neutrophil Extracellular Traps as a Biomarker for the Differential Diagnosis Between Antineutrophil Cytoplasmic Antibody-Positive Individuals With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis and Nonautoimmune Diseases

BACKGROUND/OBJECTIVE

Neutrophil extracellular traps (NETs) have a correlation with disease activity in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, it is not known whether there is an association between NETs and the presence of ANCA in other diseases. This study aimed to assess the occurrence of NETs in individuals with ANCA and whether serum NET quantitation is capable of distinguishing them with regard to the diagnosis.

METHODS

This was a cross-sectional, observational study. From the positive ANCA by indirect immunofluorescence, 94 individuals were divided into groups: AAV, infectious diseases, and neoplastic diseases. Healthy controls served for comparisons. Neutrophil extracellular traps were evaluated through the investigation of NET remnants, by detecting cell-free DNA bound to proteins such as histone, myeloperoxidase, and neutrophil elastase (NE).

RESULTS

In patients with perinuclear ANCA (p-ANCA) the detection of NETs by NE was able to distinguish AAV from infection/neoplasia and healthy controls. Receiver operating characteristic curves for serum NETs by NE in patients with p-ANCA were drawn in 2 situations: AAV versus infection/neoplasia, showing a sensitivity of 0.65 and specificity of 0.84, with an area under the curve of 65%; and AAV versus controls, showing a sensitivity of 0.84 and a specificity of 0.88, with an area under the curve of 96%.

CONCLUSIONS

For p-ANCA-positive individuals, we found higher serum NETs detected by NE-DNA in those with chronic infectious and neoplastic diseases than in AAV individuals and healthy controls. This allows us to infer that the evaluation of serum NETs may be of value as a biomarker for differential diagnosis.

Methotrexate and Non-Surgical Periodontal Treatment Change the Oral-Gut Microbiota in Rheumatoid Arthritis: A Prospective Cohort Study

This study evaluated the changes in the composition of oral-gut microbiota in patients with rheumatoid arthritis (RA) caused by methotrexate (MTX) and non-surgical periodontal treatment (NSPT). Assessments were performed at baseline (T0), 6 months after MTX treatment (T1), and 45 days after NSPT (T2). The composition of the oral and gut microbiota was assessed by amplifying the V4 region of the 16S gene from subgingival plaques and stools. The results of the analysis of continuous variables were presented descriptively and non-parametric tests and Spearman's correlation were adopted. A total of 37 patients (27 with periodontitis) were evaluated at T0; 32 patients (24 with periodontitis) at T1; and 28 patients (17 with periodontitis) at T2. MTX tended to reduce the alpha diversity of the oral-gut microbiota, while NSPT appeared to increase the number of different species of oral microbiota. MTX and NSPT influenced beta diversity in the oral microbiota. The relative abundance of oral microbiota was directly influenced by periodontal status. MTX did not affect the periodontal condition but modified the correlations that varied from weak to moderate (p < 0.05) between clinical parameters and the microbiota. MTX and NSPT directly affected the composition and richness of the oral-gut microbiota. However, MTX did not influence periodontal parameters.

Extra-articular manifestations of rheumatoid arthritis remain a major challenge: data from a large, multi-centric cohort

INTRODUCTION

Although Rheumatoid Arthritis (RA) extra-articular manifestations (ExtRA) occurrence has been decreasing over time, they are still a major mortality risk factor for patients.

OBJECTIVE

To determine the prevalence of ExtRA in a large cohort, and its association with demographic and clinical variables.

METHOD

Cross-sectional and observational study, based on a multi-centric database from a prospective cohort, in which 11 public rheumatology centres enrolled RA patients (1987 ARA or 2010 ACR-EULAR). Data collection began in 08-2015, using a single online electronic medical record. Continuous variables were compared using Mann-Whitney U-test, and Fisher's exact test or chi-square test, as appropriate, were used for categorical variables. The level of significance was set at 5% (p < 0.05).

RESULTS

1115 patients were included: 89% women, age [mean ± SD] 58.2 ± 11.5 years, disease duration 14.5 ± 12.2 years, positive Rheumatoid Factor (RF, n = 1108) in 77%, positive anti-cyclic citrullinated peptide (ACPA, n = 477) in 78%. Regarding ExtRA, 334 occurrences were registered in 261 patients, resulting in an overall prevalence of 23.4% in the cohort. The comparison among ExtRA and Non-ExtRA groups shows significant higher age (p < 0.001), disease duration (p < 0.001), RF high titers (p = 0.018), Clinical Disease Activity index (CDAI) (p < 0.001), Disease Activity Index 28 (DAS 28) (p < 0.001), and Health Assessment Questionnaire (HAQ) (p < 0.001) in ExtRA group. Treatment with Azathioprine (p = 0.002), Etanercept (p = 0.049) Glucocorticoids (GC) ('p = 0.002), and non-steroidal anti-inflammatory drugs (NSAIDs) (p < 0.001) were more frequent in ExtRA group.

CONCLUSIONS

ExtRA manifestations still show an expressive occurrence that should not be underestimated. Our findings reinforce that long-term seropositive disease, associated with significant disability and persistent inflammatory activity are the key factors related to ExtRA development.

Cytokine storm in individuals with severe COVID-19 decreases endothelial cell antioxidant defense via Downregulation of the Nrf2 transcriptional factor

The cytokine storm in SARS-CoV-2 infection contributes to the onset of inflammation and target organ damage. The endothelium is a key player in COVID-19 pathophysiology and it is an important target for cytokines. Since cytokines trigger oxidative stress and negatively impact endothelial cell function, we sought to determine whether serum derived from severe COVID-19 individuals decreases endothelial cells' main antioxidant defense, i.e. the antioxidant transcriptional factor Nrf2. Human umbilical vein endothelial cells (HUVEC) were incubated with severe COVID-19 serum at different time points and the effects on redox balance and Nrf2 activity were determined. Serum from COVID-19 individuals increased oxidant species, as indicated by higher DHE oxidation, increased protein carbonylation and augmented mitochondrial reactive oxygen species (ROS) generation and dysfunction. COVID-19 serum, in comparison with serum from healthy individuals, induced cell death and diminished nitric oxide (NO) bioavailability. In parallel, Nrf2 nuclear accumulation and the expression of Nrf2-targeted genes were reduced in endothelial cells exposed to serum from COVID-19 individuals. Additionally, these cells exhibited higher expression of Bach-1, a negative regulator of Nrf2 that competes for DNA binding. All events were prevented by Tocilizumab, an IL-6 receptor blocker, indicating that IL-6 is key to the impairment of endothelial antioxidant defense. In conclusion, endothelial dysfunction related to SARS-Cov-2 infection is linked to an IL-6-dependent decrease in the endothelial antioxidant defense. Pharmacological activation of Nrf2 may decrease endothelial cell damage in individuals with severe COVID-19.

Inhibition of IL-6 signaling prevents serum-induced umbilical cord artery dysfunction from patients with severe COVID-19

Coronavirus disease 2019 (COVID-19) infection has a negative impact on the cytokine profile of pregnant women. Increased levels of proinflammatory cytokines seem to be correlated with the severity of the disease, in addition to predisposing to miscarriage or premature birth. Proinflammatory cytokines increase the generation of reactive oxygen species (ROS). It is unclear how interleukin-6 (IL-6) found in the circulation of patients with severe COVID-19 might affect gestational health, particularly concerning umbilical cord function. This study tested the hypothesis that IL-6 present in the circulation of women with severe COVID-19 causes umbilical cord artery dysfunction by increasing ROS generation and activating redox-sensitive proteins. Umbilical cord arteries were incubated with serum from healthy women and women with severe COVID-19. Vascular function was assessed using concentration-effect curves to serotonin in the presence or absence of pharmacological agents, such as tocilizumab (antibody against the IL-6 receptor), tiron (ROS scavenger), ML171 (Nox1 inhibitor), and Y27632 (Rho kinase inhibitor). ROS generation was assessed by the dihydroethidine probe and Rho kinase activity by an enzymatic assay. Umbilical arteries exposed to serum from women with severe COVID-19 were hyperreactive to serotonin. This effect was abolished in the presence of tocilizumab, tiron, ML171, and Y27632. In addition, serum from women with severe COVID-19 increased Nox1-dependent ROS generation and Rho kinase activity. Increased Rho kinase activity was abolished by tocilizumab and tiron. Serum cytokines in women with severe COVID-19 promote umbilical artery dysfunction. IL-6 is key to Nox-linked vascular oxidative stress and activation of the Rho kinase pathway.

Comparative study of the synovial levels of RANKL and OPG in rheumatoid arthritis, spondyloarthritis and osteoarthritis

INTRODUCTION

In chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA).

METHODS

This was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed.

RESULTS

We found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA.

CONCLUSION

Within this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.

Performance of the Rheumatoid Arthritis Disease Activity Index in the Assessment of Disease Activity in Rheumatoid Arthritis-Findings From the REAL Study

BACKGROUND/OBJECTIVE

Although telemedicine use has been under discussion for decades, this topic has gained unprecedented importance during the COVID-19 pandemic. The Rheumatoid Arthritis Disease Activity Index (RADAI) is a user-friendly tool, fully self-administered, to assess rheumatoid arthritis (RA) disease activity. The aim of this study was to compare the performance of RADAI with other disease activity indices, functional status, and inflammatory markers in a large cohort of RA patients.

METHODS

We assessed the concurrent validity of RADAI against Clinical Disease Activity Index (CDAI), Disease Activity Score in 28 Joints-C-reactive protein, Disease Activity Score in 28 Joints-erythrocyte sedimentation rate, Simplified Disease Activity Index, and physician assessment of disease activity and the correlation of RADAI with Health Assessment Questionnaire-Disability Index and inflammatory markers at the REAL Study baseline. We also evaluated the correlation of the change in RADAI and the change in CDAI over a 6-month follow-up.

RESULTS

From the 1115 patients included in the REAL Study, 1113 had RADAI scores in the first assessment. At baseline, correlations between RADAI and other disease activity indices were strong, ranging from 0.64 (comparison with physician assessment) to 0.79 (comparison with CDAI). Correlation between the change in RADAI score over the 6 months of follow-up and the change in CDAI score over the same period was moderate/strong for the overall group and within the stratified analyses.

CONCLUSION

The strong correlation of RADAI with other well-established tools for disease activity measurement reassures its use with RA patients' follow-up, especially in this new era of telemedicine.

Neutrophil extracellular traps mediate joint hyperalgesia induced by immune inflammation

OBJECTIVE

To evaluate the role of neutrophil extracellular traps (NETs) in the genesis of joint hyperalgesia using an experimental model of arthritis and transpose the findings to clinical investigation.

METHODS

C57BL/6 mice were subjected to antigen-induced arthritis (AIA) and treated with Pulmozyme (PLZ) to degrade NETs or Cl-amidine to inhibit NET production. Oedema formation, the histopathological score and mechanical hyperalgesia were evaluated. NETs were injected intra-articularly in wild type (WT), Tlr4-/-, Tlr9-/-, Tnfr1-/- and Il1r-/- mice, and the levels of cytokines and Cox2 expression were quantified. NETs were also quantified from human neutrophils isolated from RA patients and individual controls.

RESULTS

AIA mice had increased NET concentration in joints, accompanied by increased Padi4 gene expression in the joint cells. Treatment of AIA mice with a peptidyl arginine deiminase 4 inhibitor or with PLZ inhibited the joint hyperalgesia. Moreover, the injection of NETs into joints of naïve animals generated a dose-dependent reduction of mechanical threshold, an increase of articular oedema, inflammatory cytokine production and cyclooxygenase-2 expression. In mice deficient for Tnfr1, Il1r, Tlr4 and Tlr9, joint hyperalgesia induced by NETs was prevented. Last, we found that neutrophils from RA patients were more likely to release NETs, and the increase in synovial fluid NET concentration correlated with an increase in joint pain.

CONCLUSION

The findings indicate that NETs cause hyperalgesia possibly through Toll-like receptor (TLR)-4 and TLR-9. These data support the idea that NETs contribute to articular pain, and this pathway can be an alternative target for the treatment of pain in RA.

Are neutrophil extracellular traps the link for the cross-talk between periodontitis and rheumatoid arthritis physiopathology?

OBJECTIVES

Neutrophil extracellular traps (NETs) play a role in the pathogenesis of periodontitis and rheumatoid arthritis (RA). However, it remains poorly understood whether NETs participate in the cross-talk between periodontitis and RA. Herein, we investigated the production of NETs in individuals with periodontitis and RA and its association with clinical parameters. The impact of periodontal therapy on RA and NET release was also assessed.

METHODS

The concentration of NETs and cytokines was determined in the saliva and plasma of individuals with early RA (n = 24), established RA (n = 64), and individuals without RA (n = 76). The influence of periodontitis on the production of NETs and cytokines was also evaluated.

RESULTS

Individuals with early RA had a higher concentration of NETs in saliva and plasma than individuals with established RA or without RA. Periodontitis resulted in an increase in the concentration of NETs of groups of individuals without RA and with early RA. The proportion of individuals with high concentrations of IL-6, IL-10 and GM-CSF was higher among individuals with periodontitis than among individuals without periodontitis. The concentrations of TNF-α, IL-6, IL-17/IL-25, and IL-28A were particularly high in individuals with early RA. Worse periodontal clinical parameters, RA onset and RA activity were significantly associated with circulating NETs. Periodontal therapy was associated with a reduction in the concentration of NETs and inflammatory cytokines and amelioration in periodontitis and RA.

CONCLUSION

This study reveals that NETs are a possible link between periodontitis and RA, with periodontal therapy resulting in a dramatic switch in circulating NET levels.

Is there an Inflammation Role for MYD88 in Rheumatoid Arthritis?

Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease with strong genetic influence, especially upon immune response components. Several cytokines from the toll-like receptors activation pathway display recognized role for RA establishment. However, few studies have verified the role of key mediators such as MYD88 gene and its genetic variants. In the present study, we aim to evaluate the rs6853 functional single-nucleotide variation (SNV) role in RA etiopathogenesis, clinical severity status, and its impact in MYD88 mRNA levels and IL-lβ protein levels. For the association study, a total of 423 RA patients and 346 health individuals, enrolled as control, from Northeast and Southeast Brazil were genotyped using specific Taqman probe. For the gene expression assays, we performed a MYD88 rs6853 genotype-guided monocyte cell culture divided into non-stimulated and lypopolysaccharides (LPS)-stimulated cells from healthy individuals. MYD88 gene expression was measured using primer specifics while IL-1β levels were evaluated by ELISA. We observed that A allele and AA genotype were associated to an increased risk to RA development (OR = 1.60; 95% CI 1.24-2.08; p = 0.0004/OR = 2.83; 95% CI 1.25-6.41; p = 0.0152). The AA genotype exhibited lower MYD88 mRNA levels than GG genotype in non-stimulated monocyte cell culture (FC - 3.83; p = 0.003). Additionally, we verified an increase of IL-1β levels when AA genotype non-stimulated monocytes were compared to AA genotype LPS-stimulates (p = 0.021). In summary, MYD88 rs6853 polymorphism associated to RA development in our Brazilian cohort and showed influence upon MYD88 mRNA levels' expression and IL-lβ production.

T-cell specific upregulation of Sema4A as risk factor for autoimmunity in systemic lupus erythematosus and rheumatoid arthritis

The aim of the present study was to evaluate the impact of SEMA4A genetic variants on expression of sema4A protein and its relation to autoimmunity development in Systemic Lupus Erythematosus and Rheumatoid Arthritis patients. A total of 541 SLE patients, 390 RA patients and 607 healthy individuals were genotyped. We also assessed SEMA4A mRNA expression from whole blood cells and the in vitro protein production from resting and activated T lymphocytes as well as mature dendritic cells from healthy individuals stratified according to their genotypes for SLE/RA associated SEMA4A variants. Our results showed that T/T genotype for rs3738581 SNP is associated with both RA and SLE development (p = .000053, OR = 2.35; p = .0019, OR = 2.07, respectively; statistical power = 100%) and also to an increased in vitro sema4A production in active T lymphocytes. Our findings are indicative of a T cell-specific upregulation of sema4A in the presence of T/T genotype, being a risk factor for SLE and RA.

2017 recommendations of the Brazilian Society of Rheumatology for the pharmacological treatment of rheumatoid arthritis

The objective of this document is to provide a comprehensive update of the recommendations of Brazilian Society of Rheumatology on drug treatment of rheumatoid arthritis (RA), based on a systematic literature review and on the opinion of a panel of rheumatologists. Four general principles and eleven recommendations were approved. General principles: RA treatment should (1) preferably consist of a multidisciplinary approach coordinated by a rheumatologist, (2) include counseling on lifestyle habits, strict control of comorbidities, and updates of the vaccination record, (3) be based on decisions shared by the patient and the physician after clarification about the disease and the available therapeutic options; (4) the goal is sustained clinical remission or, when this is not feasible, low disease activity. Recommendations: (1) the first line of treatment should be a csDMARD, started as soon as the diagnosis of RA is established; (2) methotrexate (MTX) is the first-choice csDMARD; (3) the combination of two or more csDMARDs, including MTX, may be used as the first line of treatment; (4) after failure of first-line therapy with MTX, the therapeutic strategies include combining MTX with another csDMARD (leflunomide), with two csDMARDs (hydroxychloroquine and sulfasalazine), or switching MTX for another csDMARD (leflunomide or sulfasalazine) alone; (5) after failure of two schemes with csDMARDs, a bDMARD may be preferably used or, alternatively a tsDMARD, preferably combined, in both cases, with a csDMARD; (6) the different bDMARDs in combination with MTX have similar efficacy, and therefore, the therapeutic choice should take into account the peculiarities of each drug in terms of safety and cost; (7) the combination of a bDMARD and MTX is preferred over the use of a bDMARD alone; (8) in case of failure of an initial treatment scheme with a bDMARD, a scheme with another bDMARD can be used; in cases of failure with a TNFi, a second bDMARD of the same class or with another mechanism of action is effective and safe; (9) tofacitinib can be used to treat RA after failure of bDMARD; (10) corticosteroids, preferably at low doses for the shortest possible time, should be considered during periods of disease activity, and the risk-benefit ratio should also be considered; (11) reducing or spacing out bDMARD doses is possible in patients in sustained remission.

Lapachol, a compound targeting pyrimidine metabolism, ameliorates experimental autoimmune arthritis

Background

The inhibition of pyrimidine biosynthesis by blocking the dihydroorotate dehydrogenase (DHODH) activity, the prime target of leflunomide (LEF), has been proven to be an effective strategy for rheumatoid arthritis (RA) treatment. However, a considerable proportion of RA patients are refractory to LEF. Here, we investigated lapachol (LAP), a natural naphthoquinone, as a potential DHODH inhibitor and addressed its immunosuppressive properties.

Methods

Molecular flexible docking studies and bioactivity assays were performed to determine the ability of LAP to interact and inhibit DHODH. In vitro studies were conducted to assess the antiproliferative effect of LAP using isolated lymphocytes. Finally, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA) models were employed to address the anti-arthritic effects of LAP.

Results

We found that LAP is a potent DHODH inhibitor which had a remarkable ability to inhibit both human and murine lymphocyte proliferation in vitro. Importantly, uridine supplementation abrogated the antiproliferative effect of LAP, supporting that the pyrimidine metabolic pathway is the target of LAP. In vivo, LAP treatment markedly reduced CIA and AIA progression as evidenced by the reduction in clinical score, articular tissue damage, and inflammation.

Conclusions

Our findings propose a binding model of interaction and support the ability of LAP to inhibit DHODH, decreasing lymphocyte proliferation and attenuating the severity of experimental autoimmune arthritis. Therefore, LAP could be considered as a potential immunosuppressive lead candidate with potential therapeutic implications for RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1236-x) contains supplementary material, which is available to authorized users.

Is HLA class II susceptibility to primary antiphospholipid syndrome different from susceptibility to secondary antiphospholipid syndrome?

To assess whether the major histocompatibility complex (MHC) profile of patients presenting with primary antiphospholipid syndrome (PAPS) is different from that of patients with secondary antiphospholipid syndrome (SAPS), we studied 123 patients, 34 of whom presented PAPS and 35 SAPS due to systemic lupus erythematosus (SLE), 54 SLE patients without antiphospholipid syndrome (APS), and 166 controls. HLA-DRB1 and DQB1 alleles were typed using amplified DNA hybridized with sequence-specific primers. Compared to controls, PAPS patients exhibited a nonsignificantly increased frequency of DR53-associated alleles, and SAPS patients presented an increased frequency of HLA-DRB1* 03 alleles (corrected P 0.05). In addition, HLA-DRB1* 03 alleles were over-represented in SAPS patients presenting anticardiolipin antibody (aCL) (Pc 0.02), in SLE patients as a whole (Pc < 0.0001), and in SLE patients without APS (Pc 0.02). The frequency of aCL among SLE patients presenting or not HLA-DRB1* 03 alleles was closely similar. A trend to an increase in the frequency of the DQB1* 0604 allele (14.3 versus 4.2%, P 0.03) and of the DQB1*0302 allele (31.4 versus 12.7%, P 0.01) was observedin SAPS. Taken together, these results indicate that the association of SAPS with HLA-DRB1* 03 is due to the association with SLE and is not due to aCL, and suggest that the HLA class II profile of PAPS is different from that of SAPS.

Interleukin-18, interleukin-12B and interferon-γ gene polymorphisms in Brazilian patients with rheumatoid arthritis: a pilot study

Polymorphisms in interleukin (IL)-18, IL-12 and interferon (IFN)-γ genes are associated with different levels of cytokines expression and have been associated with rheumatoid arthritis (RA). IL-18 +105 A/C, IL-12B +1188 A/C and IFN-γ +874 T/A polymorphisms were analyzed by restriction fragment length polymorphism-polymerase chain reaction (PCR) and amplification refractory mutation system PCR from 90 RA patients and 186 healthy individuals. There were significant differences to IL-18 +105 A/C polymorphism between the RA and control groups (odds ratio = 3.77; P < 0.0001). Individual carriers of the variant allele C had a 3.77-fold increased risk of for RA (P = 0.0032). No association was observed for IL-12B and IFN-γ polymorphisms. Our finds suggest a possible role for IL-18 polymorphism in the RA susceptibility in studied population.

Coronary thrombosis as the first complication of antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune thrombophilia, characterized by the presence of plasma antibodies against phospholipids, associated with recurrent episodes of venous and/or arterial thrombosis and gestational morbidity (especially recurrent miscarriage). We report the case of a young female patient diagnosed with systemic lupus erythematosus (SLE) associated with the presence of antiphospholipid antibodies for a long time, presenting with acute myocardial infarction (AMI) due to proximal thrombosis of the anterior descending artery as the first clinical complication of APS.

2012 Brazilian Society of Rheumatology Consensus for the treatment of rheumatoid arthritis

OBJECTIVE

To elaborate recommendations for the treatment of rheumatoid arthritis in Brazil.

METHOD

Literature review with articles' selection based on evidence and the expert opinion of the Rheumatoid Arthritis Committee of the Brazilian Society of Rheumatology.

RESULTS AND CONCLUSIONS

1) The therapeutic decision should be shared with the patient; 2) immediately after the diagnosis, a disease-modifying antirheumatic drug (DMARD) should be prescribed, and the treatment adjusted to achieve remission; 3) treatment should be conducted by a rheumatologist; 4) the initial treatment includes synthetic DMARDs; 5) methotrexate is the drug of choice; 6) patients who fail to respond after two schedules of synthetic DMARDs should be assessed for the use of biologic DMARDs; 7) exceptionally, biologic DMARDs can be considered earlier; 8) anti-TNF agents are preferentially recommended as the initial biologic therapy; 9) after therapeutic failure of a first biologic DMARD, other biologics can be used; 10) cyclophosphamide and azathioprine can be used in severe extra-articular manifestations; 11) oral corticoid is recommended at low doses and for short periods of time; 12) non-steroidal anti-inflammatory drugs should always be prescribed in association with a DMARD; 13) clinical assessments should be performed on a monthly basis at the beginning of treatment; 14) physical therapy, rehabilitation, and occupational therapy are indicated; 15) surgical treatment is recommended to correct sequelae; 16) alternative therapy does not replace traditional therapy; 17) family planning is recommended; 18) the active search and management of comorbidities are recommended; 19) the patient's vaccination status should be recorded and updated; 20) endemic-epidemic transmissible diseases should be investigated and treated.

Ocular findings in a patient with Castleman's disease before and after treatment with immunosuppression and plasmapheresis

A 12-year-old girl with a 3-month history of epistaxis and Castleman's disease presented with blurred vision in both eyes for 2 weeks. Indirect ophthalmoscopy revealed a blurred optic disc margin, venous engorgement and tortuosity, intraretinal hemorrhages and cotton wool spots, and serous detachment of the neurosensory retina in the posterior pole of each eye. Fluorescein angiography and laboratory tests revealed abnormalities consistent with the clinical examination. Six months following institution of immunosuppressive treatment, cryoglobulin levels decreased and visual acuity and funduscopic abnormalities were markedly improved. However, a few microaneurysms, retinal hemorrhages, and venous engorgement and tortuosity persisted. One month after the cessation of immunosuppressive treatment, symptoms related to the hyperviscosity syndrome recurred and the patient was treated with one session of plasmapheresis. One month after the plasmapheresis, the patient's symptoms resolved, laboratory values were normal, visual acuity was 20/15 in both eyes, and the funduscopic examination of each eye was unremarkable.

Shared and unique gene expression in systemic lupus erythematosus depending on disease activity

Patients presenting with active systemic lupus erythematosus (SLE) manifestations may exhibit distinct pathogenetic features in relation to inactive SLE. Also, cDNA microarrays may potentially discriminate the gene expression profile of a disease or disease variant. Therefore, we evaluated the expression profile of 4500 genes in peripheral blood lymphocytes (PBL) of SLE patients. We studied 11 patients with SLE (seven with active SLE and four with inactive SLE) and eight healthy controls. Total RNA was isolated from PBL, reverse transcribed into cDNA, and postlabeled with Cy3 fluorochrome. These probes were then hybridized to a glass slide cDNA microarray containing 4500 human IMAGE cDNA target sequences. An equimolar amount of total RNA from human cell lines served as reference. The microarray images were quantified, normalized, and analyzed using the R environment (ANOVA, significant analysis of microarrays, and cluster-tree view algorithms). Disease activity was assessed by the SLE disease activity index. Compared to the healthy controls, 104 genes in active SLE patients (80 repressed and 24 induced) and 52 genes in nonactive SLE patients (31 induced and 21 repressed) were differentially expressed. The modulation of 12 genes, either induced or repressed, was found in both disease variants; however, each disease variant had differential expression of different genes. Taken together, these results indicate that the two lupus variants studied have common and unique differentially expressed genes. Although the biological significance of the differentially expressed genes discussed above has not been completely understood, they may serve as a platform to further explore the molecular basis of immune deregulation in SLE.

HLA class I and class II profiles of patients presenting with Sydenham's chorea

Sydenham's chorea (SC) may occur in rheumatic fever (RF) patients without arthritis and carditis. In this study we typed HLA antigens and alleles in patients presenting with the distinct major clinical manifestations of RF, i.e., chorea, carditis, or arthritis, in population and family studies. We evaluated 91 patients with RF for HLA-A, HLA-B, and HLA-DR antigens; of these, 33 had pure chorea, 26 pure carditis, 16 pure arthritis, and 16 carditis plus arthritis. We also typed 24 SC patients and their unaffected siblings for HLA-DRB1 and HLA-DQB1 alleles using molecular methods. HLA-B49 and HLA-DR1 antigens were overrepresented in the total group of patients with RF and in all the subgroups studied, excluding the SC subgroup in which the frequency of HLA-DR1 antigen was not increased. The frequencies of the HLA-DRB1 and HLA-DQB1 alleles in patients with pure chorea were not significantly different from those observed in controls. Similarly, the frequencies of HLA class II alleles in SC patients did not differ significantly from those observed in unaffected siblings. These findings show that immunogenetic susceptibility to RF varies according to the major clinical manifestation presented by the patient.

Glutamate Release in Experimental Ischaemia of the Retina: An Approach Using Microdialysis

A rabbit eye model of neural ischaemia is described that uses an increased pressure in the anterior eye chamber to block the capillary supply to the retina. A microdialysis probe placed very close to the retinal surface was used to monitor release of amino acids during ischaemia. A large (two- to threefold) increase in the release of glutamate and O-phosphoserine (twofold), but not of six other amino acids monitored, occurred during initial ischaemia. During reperfusion after release of intraocular pressure, much larger (five- to 10-fold) increases in the release of these amino acids were observed. Parallel ischaemic retinal tissue damage was observed. This damage was prevented by ketamine applied locally via a superfusion needle, suggesting that glutamate released during ischaemia, and particularly during reperfusion, was responsible for cell death.