Anti-citrullinated Antibodies Research Articles

Impact of anti-human IgG hinge peptide antibodies on identification of patients with early seronegative rheumatoid arthritis.

The early diagnosis of seronegative rheumatoid arthritis (SNRA), characterised by the absence of rheumatoid factor and anti-citrullinated antibody, involves a greater challenge compared to seropositive RA (SPRA). This study aimed to assess the discriminatory potential of anti-human IgG hinge antibodies (AHAs) for patients with early SNRA. DMARDs-naive patients with SPRA (n=43), SNRA (n=21), and non-RA (n=49), with disease duration < 2 years, were included. Antigens comprised IgG1 or IgG4 F(ab')2 cleaved by pepsin or MMP-3 and their hinge peptide analogues. Eight IgG anti-hinge antibodies (AHAs) against these antigens were measured in sera from the patients and 58 healthy controls (HCs) using ELISA. Serum CRP and MMP-3 levels, and clinical disease activity index (CDAI), were obtained from medical records. The area under the curve (AUC) obtained from logistic regression and receiver operating characteristic curve analyses were used as a discriminant indicator. The levels of the IgG AHAs were as follows: SPRA≥SNRA≈non-RA>HC. None of the AHAs were effective in discriminating SNRA from non-RA. However, the combination of MMP-3 and AHAs against IgG4 hinge peptide analogues demonstrated the utility (AUC=0.94). Furthermore, combination of MMP-3, AHAs against IgG1 hinge peptide analogues and CDAI maximally exerted discriminatory power (AUC=0.997). Specific AHAs in combination with MMP-3 and CDAI are potentially useful to discriminate SNRA from non-RA.

Osteopontin, osteoprotegerin and musculoskeletal ultrasound findings in first-degree relatives of rheumatoid arthritis: potential markers of preclinical disease

BackgroundFirst-degree relatives (FDRs) of rheumatoid arthritis (RA) patients are known to have increased risk of developing the disease. The detection of altered bone metabolism in FDRs could be a predictor of the disease. Musculoskeletal ultrasound (MSUS) is known for its ability to detect subclinical joint inflammation in RA, but changes in FDRs are not yet described. We aimed to study serum Osteopontin (OPN) and Osteoprotegerin (OPG) levels in FDRs of RA patients as markers of altered bone metabolism in relation to clinical, laboratory and musculoskeletal ultrasound (MSUS) findings.MethodsFifty-five individuals were included, 20 had definite RA, 25 were first degree relatives (FDRs) of RA patients, and 10 healthy controls. Clinical evaluation for joint swelling/tenderness was performed for all. ESR, CRP, rheumatoid factor (RF), anti-citrullinated antibodies (ACPA), OPN, OPG, and Musculoskeletal ultrasound (MSUS) by the US7 score were evaluated.ResultsOsteoprotegerin was significantly higher in RA (143.89 pg/ml ± 365.47) than in FDRs (22.23 pg/ml ± 65.73; p = 0.009) and controls (6.20 pg/ml ± 12.43; p = 0.003). OPN was also higher in RA (3.66 ng/ml ± 4.20) than in FDRs (1.97 ng/ml ± 1.04) and controls (2.81 ng/ml ± 1.31), though not significant (p = 0.102). Eight of 25 FDRs (32%) had arthralgia without clinical arthritis and 17/25 (68%) were asymptomatic. FDRs with arthralgia had significantly higher ESR and CRP levels than asymptomatic FDRs (9.82 mm/h ± 4.13; p = 0.003, and 3.93 mg/l ± 3.58; p = 0.003). Osteoprotegerin was higher in FDRs than in controls, and also in those with arthralgia (51.55 pg/ml ± 114.68) than in those without (8.44 pg/ml ± 9.67), though without significant difference. OPN was higher in FDRs with arthralgia (2.09 ng/ml ± 1.19) than in asymptomatic (1.70 ng/ml ± 0.55), also without significant difference. Pathologic findings by US7 were detected in 10/25 (40%) FDRs, of which three (12%) had arthralgia and seven (28%) were asymptomatic.ConclusionsThe raised OPG and lower OPN in FDRs than in controls reflect an altered bone metabolism which could precede clinical disease phase. OPN and OPG could serve as markers of altered preclinical bone metabolism in FDRs of RA. US7 score might be a useful screening tool to identify ‘at-risk’ individuals.

The clinical case of a combination of ankylosing spondylitis, ulcerative colitis and rheumatoid arthritis in one patient: where is the intersection point?

We describe a clinical observation of a 64-year old Caucasian patient with a longstanding ankylosing spondylitis, who was admitted to the clinic for diarrhea and joint syndrome. Physical and X-ray examination showed that his musculoskeletal system disorder was represented by ankylosing spondylitis, symmetrical erosive polyarthritis of the metacarpophalangeal joints, and wrist joint ankylosis. Laboratory work-up identified that the patient was HLA-B27 positive, had high rheumatoid factor and anti-citrulline antibodies levels. At colonoscopy, there were signs of ulcerative colitis. After the differential diagnosis procedures, we were able to conclude that the patient had a combination of rheumatoid arthritis, ankylosing spondylitis, and ulcerative colitis as three independent but associated disorders. The first description of these three autoimmune diseases in one patient can be of interest for clinicians.

Usefulness of Lung Ultrasound as a Method for Early Diagnosis of Interstitial Lung Disease in Patients with Rheumatoid Arthritis.

To determine the value of lung ultrasound (LUS) compared to high-resolution computed tomography (HRCT) in the early diagnosis of interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA). An observational prospective study was performed. Were included patients with respiratory symptoms or/and, patients with crackles in auscultation during medical consultation. All patients underwent to chest X-rays, LUS, HRCT,and respiratory function tests. A total of 192 patients with RA were included. Mean disease duration was 16.8 ± 11.1 years. 72% were positive for rheumatoid factor or anti-citrullinated antibodies. Of the total number of subjects, 54.7% had respiratory symptoms. The other patients did not have respiratory symptoms, but they did have had crackles on pulmonary auscultation. B lines > 11.5 on the ROC curve predicted ILD (AUC 0.63; CI 95%: 0.55-0.71; p < 0.003). A DLCO value of <7.13 significantly predicted the presence of ILD (AUC 0.61; 95% CI: 0.52-0.70; p < 0.028). The findings of this study suggest that LUS is a valuable tool for the early diagnosis of ILD in patients with RA, and together with DLCO, can adequately predict the presence of ILD in this population. LUS also helps to determine which patients with respiratory symptoms and signs suggestive for ILD are undergo to HRCT.

Pathogenetic role of neutrophil extracellular traps in coronary flow impairment following percutaneous coronary intervention in acute myocardial infarction patients -A multicenter study-

Abstract Background A suicidal function of neutrophils to ensnare and kill microbes by expelling neutrophil extracellular traps (NETs) via histone citrullination and chromatin decondensation has emerged as it enhances local inflammation and thrombogenicity at the culprit lesion of acute myocardial infarction (AMI). Purpose This multicenter study was aimed to examine 1) the histopathological feature of coronary thrombus with the NETs formation in AMI patients, and 2) the association of NETs with impaired coronary flow after percutaneous coronary intervention (PCI) for AMI patients. Methods Coronary thrombi were obtained from 44 patients with AMI [male; 77%, age; 69±12(SD) y-o)]who underwent PCI within 24 hours from the onset. Aspirated thrombi were immediately bisected and frozen, and 5-µm thickness unstained sections were processed for polarized light microscopy (PLM) imaging and immunofluorescence staining. NETs were immunohistochemically defined when objects were co-stained with anti-myeloperoxidase and anti-citrullinated histone H3 antibodies (Figure A,B). Adjacent sections were stained with Masson’s trichrome to measure the whole thrombus area. The ImageJ1 software was utilized for the automatic segmentation on the digitized histology images. Segmented NETs area was divided by the thrombus area as a measure of NETs. Clinical characteristics, including AMI subset, post PCI final TIMI flow grade and TIMI frame count, were collected. Results All aspirated thrombi exhibited NETs (Figure A), and then subjects were split into 2 groups with a median value of NETs (62.8 x10-4 um2/um2); high-NETs and low-NETs groups. Patient characteristics were all comparable between the 2 groups. PLM results showed that birefringent crystals, suggestive of cholesterol crystals, were more frequently noted in the thrombi with high-NETs compared with those with low-NETs (50.0% vs. 13.6%, P=0.010). In the immunofluorescence, NETs were seen in the proximity of the crystals (Figure B). The multivariable analysis with covariates of age, sex, major coronary risk factors, MI related to left anterior descending artery and the onset to aspiration time revealed that the presence of birefringent crystals remained an independent predictor for high-NETs formation [OR=5.78, 95%CI=1.13-29.66, P=0.035]. In the high-NETs group, the prevalence of the final TIMI flow grade 3 was significantly lower than the low-NETs group (63.6% vs. 90.9 %, P=0.031). Likewise, there was a significant positive correlation between NETs area and TIMI frame count, defined as the number of cineframes required for contrast to reach a standardized distal coronary landmark (R=0.681, P&amp;lt;0.001). Conclusion The present study demonstrated that NETs were highly expressed in coronary thrombus aspirated from AMI patients in association with crystalline components, relating to coronary flow impairment following PCI in AMI patients.

Antibodies to cyclic citrullinated peptide and angiopoietin-like protein type 4 as markers of immune inflammation and osteoporotic processes in rheumatoid arthritis patients

Low-energy fractures in rheumatoid arthritis (RA) are more common in patients with high activity and long duration of disease, and with high titers of anti-citrullinated antibodies (ACPA). Increased expression of angiopoietin-like protein type 4 (ANGPTL4) in bone tissue has also been noted in inflammatory arthritis. The purpose of the present study was to analyze the effect of ACPA and ANGPTL4 on systemic bone mineral density in RA patients. Antibodies to ACPA and ANGPTL4 content were detected in blood serum of 96 RA patients (women, 91.7%) by enzyme immunoassay. Mineral density of the lumbar vertebrae (BMDL1-L4), hip neck, and entire femur (BMDtotal) was measured by dual-energy X-ray absorptiometry (DXA). In study group, the ACPA and ANGPTL4 tests were positive in 61.5% and 41.7% of patients, respectively. Negative correlations were shown between ACPA and BMDtotal, and of ANGPTL4 with BMDL1-L4 (p &lt; 0.05). Separation of the patients into groups with low (n = 34) and high (n = 62) DAS28 activity demonstrated a significant increase in ACPA with increasing RA activity (p = 0.042). ACPA and ANGPTL4 scores were also significantly higher in the group of 45 RA patients with osteoporosis (OP) compared to the RA group without OP (n = 51) showing significant difference at p = 0.002 and p = 0.028, respectively. Patients’ age, body mass index (BMI), duration and activity of the disease had no significant effect on ACPA in the general group of RA patients. However, the correlation between ACPA and DAS28 proved to be significant in the group of RA patients with OP (b = 0.31, p = 0.039). Among all presented variables, the disease duration was the only significant factor for ANGPTL4 in the total group of RA patients (b = 0.31, p = 0.039). In the regression model, BMDtotal showed similar correlations with patients’ age (b = -0.28), BMI (b = 0.25), and ACPA level (b = -0.26). A search for association between BMDL1-L4 and various RA characteristics demonstrated a strong correlation with ANGPTL4 only (b = -0.74; R2 = 0.57). The revealed correlation between ANGPTL4 and decreased BMD specifically in the spongy layer of bone allows us to identify the RA patients with high ANGPTL4 levels as a risk group specifically for spinal fractures thus considering ANGPTL4 as a potential target for treatment of osteoporotic disorders.

Peculiarities of immunological manifestations in patients with rheumatoid arthritis in the presence of chronic infection with &lt;i&gt;Helicobacter pylori&lt;/i&gt; variant encoding cytotoxin-associated gene A

The study aimed to evaluate the association between cyclic citrullinated peptide antibody seropositivity and chronic Helicobacter pylori (H. pylori) infection in patients with rheumatoid arthritis (RA). We examined 92 women with moderate RA activity. Serum antibodies to cyclic citrullinated peptide (antiCCP), antibodies to H. pylori (anti-H. pylori-IgG), and total antibodies to H. pylori CagA antigen (antiCagA) were determined by enzyme immunoassay; the presence of anti-CagA-IgG positivity was confirmed by immunoblot. 68.5% of RA patients were positive for anti-H. pylori-IgG, and 44.4% of patients in this group were positive for anti-CagA-IgG. All the study participants were divided into three groups: I – H. pylori seronegative (H. pylori- ); II – H. pylori positive, CagA negative (H. pylori+/CagA- ); III – H. pylori positive and CagA positive (CagA+). The anti-CCP values in RA patients with CagA+ (group III) were significantly higher not only in comparison with patients seronegative for H. pylori (p &lt; 0.001), but also in comparison with patients from group II (H. pylori+/CagA- ) (p = 0.041). A study of the influence of the RA activity, the presence of RF and H. pylori on anti-CCP content demonstrated a small proportion of anti-CCP variability (R2 = 0.09), with a high contribution of H. pylori (beta = 0.25). The addition of the CagA(+) index (beta = 0.503) to the presented model allowed us to describe the variability of anti-CCP in almost 30% of cases (R2 = 0.29). In the group of RA patients with anti-CCP values exceeding the established threshold value of 20 U/mL (normal index), there was an increase in the proportion of patients infected with H. pylori (p &lt; 0.001), but not the proportion of CagA-positive patients (p = 0.06). When the threshold level was increased to 60 U/mL (three times the upper limit of normal) in patients with significantly high anti-CCP, the association with positivity for CagA became significant (p = 0.005). CagA is highly immunogenic and is capable of inducing an inflammatory response in the host that goes beyond the effect of H. pylori itself. Additional experimental studies are needed to investigate possible clinical and laboratory associations that may influence the treatment tactics of CagA+ patients with RA who are seropositive for anti-citrullinated antibodies, as well as to evaluate the possible effects of therapeutic intervention aimed at the eradication of H. pylori in this group.

The Influence of Anti-Citrullinated Polypeptide Antibodies on Bone Mineral Density Decrease and Incident Major Osteoporotic Fractures in Patients with Rheumatoid Arthritis: A Retrospective Case-Control Study

Background: Effects of anti-citrullinated polypeptide antibodies (ACPA) on the bone mineral density (BMD) reduction and incidence of major osteoporotic fractures (MOF) in patients with rheumatoid arthritis (RA) were evaluated using a retrospective longitudinal case-control study. Methods: Patients with RA who were examined using dual-energy X-ray absorptiometry and simultaneously treated for more than 5 years were recruited. BMD absolute value and Z-scores at initial measurements (baseline) and changes of these values from baseline were assessed, and associations between BMD and candidate risk factors including ACPA positivity and serum titer levels were statistically evaluated. Additional statistical evaluations of ACPA positivity in regard to the incidence of MOF were tested. Results: A total of 222 patients were included. Higher ACPA titers correlated significantly with lower BMD and Z-scores at baseline using a multivariate model (p &lt; 0.05). ACPA positivity correlated significantly with lower values and an annual decrease in the Z-score in total hip at follow-up using a univariate model (p &lt; 0.05), whereas no significant correlation was found using a multivariate model. Z-scores in the ACPA-positive group were significantly lower than those of the ACPA-negative group (p &lt; 0.05). However, ACPA-positivity demonstrated no higher risk for incident MOF. Conclusions: The presence of ACPA is a potential risk of BMD loss however weak.

Identification of anti-citrullinated osteopontin antibodies and increased inflammatory response by enhancement of osteopontin binding to fibroblast-like synoviocytes in rheumatoid arthritis

BackgroundAnti-citrullinated protein/peptide antibodies (ACPAs) are present in patients at onset and have important pathogenic roles during the course of rheumatoid arthritis (RA). The characteristics of several molecules recognized by ACPA have been studied in RA, but the positivity rate of autoantibodies against each antigen is not high, and the pathogenic mechanism of each antibody is not fully understood. We investigated the role of anti-citrullinated osteopontin (anti-cit-OPN) antibodies in RA pathogenesis.MethodsEnzyme-linked immunosorbent assays on RA patients’ sera were used to detect autoantibodies against OPN. Fibroblast-like synoviocytes (FLS) isolated from RA patients were used to test the binding activity and inflammatory response of OPN mediated by anti-cit-OPN antibodies, and their effect was tested using an inflammatory arthritis mouse model immunized with cit-OPN. Anti-cit-OPN antibody positivity and clinical characteristics were investigated in the patients as well.ResultsUsing sera from 224 RA patients, anti-cit-OPN antibodies were positive in approximately 44% of RA patients, while approximately 78% of patients were positive for the cyclic citrullinated peptide (CCP2) assay. IgG from patients with anti-cit-OPN antibody increased the binding activity of OPN to FLSs, which further increased matrix metalloproteinase and interleukin-6 production in TNF-stimulated FLSs. Mice immunized with cit-OPN antibodies experienced severe arthritis. Anti-cit-OPN antibodies in RA patients decreased the drug survival rate of tumor necrosis factor (TNF) inhibitors, while it did not decrease that of CTLA4-Ig.ConclusionsAnti-cit-OPN antibodies were detected in patients with RA. IgG from patients with anti-cit-OPN antibodies aggravated RA, and anti-cit-OPN antibody was a marker of reduced the survival rate of TNF inhibitors in RA patients.

Matrix Metalloproteinase-9 Level in Synovial Fluid-Association with Joint Destruction in Early Rheumatoid Arthritis.

Background and objective: Matrix metalloproteinases (MMPs) are the key enzymes in the pathogenesis of cartilage and joint damage and potentially a new biomarker of the early erosive form of rheumatoid arthritis (RA). Firstly, the study aimed to compare the level of MMP-9 in plasma (PL) and synovial fluid (SF) of patients with RA and osteoarthritis (OA). Secondly, the goal was to examine the association of MMP-9 level in PL and SF with early erosive changes in RA, and finally, to determine the association of MMP-9 level with serological parameters of the disease (rheumatoid factor-RF and anti-citrulline protein antibodies-ACPA). Materials and Methods: A total of 156 subjects were involved in this study (84 patients with RA and 72 patients with OA, who were involved as a control group). MMP-9 level was measured in PL and SF of all subjects by the sandwich enzyme-linked immunosorbent assay (ELISA) method. Standard radiographs of the hands and feet were used to detect joint damage and classification into erosive or non-erosive RA. The Larsen score (LS) was used for the quantitative assessment of joint damage, and its annual change (∆ LS) was used to assess the radiographic progression of the disease. Results: MMP-9 level in PL and SF was significantly higher in RA compared to controls (PL: 19.26 ± 7.54 vs. 14.57 ± 3.11 ng/mL, p&lt; 0.01; SF: 16.17 ± 12.25 vs. 0.75 ± 0.53 ng/mL, p &lt; 0.001) as well as in SF of patients with erosive compared to non-erosive RA (18.43 ± 12.87 vs. 9.36 ± 7.72; p &lt; 0.05). Faster radiographic progression was recorded in erosive compared to non-erosive early RA (11.14 ± 4.75 vs. 6.13 ± 2.72; p &lt; 0.01). MMP-9 level in SF, but not in PL, significantly correlates with the radiographic progression in both erosive and non-erosive RA (ρ = 0.38 and ρ = 0.27). We did not find a significant association between RF and MMP-9 level in early RA, but the ACPA level significantly correlates with MMP-9 level in SF (r = 0.48). Conclusion: The level of MMP-9 in plasma and synovial fluid of patients with RA is significantly higher compared to patients with osteoarthritis. The level of MMP-9 in synovial fluid is significantly higher in erosive than non-erosive early RA. It is significantly associated with the radiographic progression of the disease and the level of anti-citrulline protein antibodies.

Anticitrullinated antibodies recognize rheumatoid arthritis associated T-cell epitopes modified by bacterial L-asparaginase.

Citrullinated proteins and anti-citrullinated protein antibodies (ACPAs) play an important role in the pathogenesis of rheumatoid arthritis (RA). It has been suggested that during inflammation or dysbiosis, bacteria could initiate production of ACPAs. Most patients with RA are seropositive for ACPAs, but these antibodies have overlapping reactivity to different posttranslational modifications (PTMs). For initiation and development of RA, T lymphocytes and T cell epitopes are still required. In this study, we evaluated the ability of bacterial L-asparaginase to modify RA-related T cell epitopes within type II collagen (CII259-273 and CII311-325), as well as whether these modified epitopes are recognized by ACPAs from RA patients. We included 12 patients with early RA and 11 healthy subjects selected according to predefined specific criteria. LC-MS/MS analyses revealed that the bacterial L-asparaginase can modify investigated T cell epitopes. ELISA tests showed cross-reactivity of ACPA positive sera from early RA patients towards the enzymatically modified immunodominant T cell epitopes within type II collagen (CII), but not to the modified irrelevant peptides. These data suggest that the cross-reactive ACPAs recognize the "carbonyl-Gly-Pro" motif in CII. Moreover, the T cell recognition of the modified major immunodominant T cell epitope Gal264-CII259-273 was not affected. This epitope was still able to activate autoreactive T cells from early RA patients. It is likely that such modifications are the missing link between the T cell priming and the development of anti-modified protein antibodies (AMPAs). Our results provide additional information on the etiology and pathogenesis of RA.

ASSOCIATION OF SOME IMMUNOLOGICAL BIOMARKERS WITH RHEUMATOID ARTHRITIS PATIENTS IN THI-QAR PROVINCE.

The aim: The aim of this research is to evaluate some immunological biomarkers in cases of Rheumatoid arthritis and to verify their correlation with activity of disease among the population of Thi-Qar province. Matherials and methods: This study included 45 cases of rheumatoid arthritis and 45 healthy subjects. All cases underwent complete history taking, thor¬ough clinical examination, and laboratory tests including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Anti-citrulline antibody (Anti-CCP) and rheumatoid factor (RF). IL-17and TNF-α blood level was measured by Enzyme Linked Immunosorbent Assay (ELISA) method. DAS-28 (Disease activity score 28) was evaluated. Results: Serum levels TNF-α was higher in Rheumatoid arthritis patients (424.3±19.46 pg/ml) than in healthy individuals (112.7±4.73 pg/ml), and IL-17 blood levels were higher in Rheumatoid arthritis patients (233.5±241.4 pg/ml) than the healthy individuals group (47.24±49.7 pg/ml). There was significant association found among IL-17, DAS-28, CRP and hemoglobin levels. Conclusions: In conclusion, IL-17 blood levels were significantly increased in peoples with rheumatoid arthritis than in healthy individuals. Its significant relationship with DAS-28 suggested that the level of IL-17 in serum could be important immunological biomarker for activity of disease in disease of Rheumatoid arthritis.

MiRNA-Mediated Epigenetic Regulation of Treatment Response in RA Patients-A Systematic Review.

This study aimed to evaluate the role of microRNAs (miRNA) as biomarkers of treatment response in rheumatoid arthritis (RA) patients through a systematic review of the literature. The MEDLINE and Embase databases were searched for studies including RA-diagnosed patients treated with disease-modifying antirheumatic drugs (DMARDs) that identify miRNAs as response predictors. Review inclusion criteria were met by 10 studies. The main outcome of the study was the response to treatment, defined according to EULAR criteria. A total of 839 RA patients and 67 healthy donors were included in the selected studies. RA patients presented seropositivity for the rheumatoid factor of 74.7% and anti-citrullinated C-peptide antibodies of 63.6%. After revision, 15 miRNAs were described as treatment response biomarkers for methotrexate, anti-tumour necrosis factor (TNF), and rituximab. Among treatments, methotrexate presented the highest number of predictor miRNAs: miR-16, miR-22, miR-132, miR-146a and miR-155. The most polyvalent miRNAs were miR-146a, predicting response to methotrexate and anti-TNF, and miR-125b, which predicts response to infliximab and rituximab. Our data support the role of miRNAs as biomarkers of treatment response in RA and point to DMARDs modifying the miRNAs expression. Nevertheless, further studies are needed since a meta-analysis that allows definitive conclusions is not possible due to the lack of studies in this field.

Antibodies against a mutated citrullinated vimentin in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by autoantibodies against citrullinated antigens. The anti-cyclic citrullinated peptide (Anti-CCP) test is commonly used to diagnose rheumatoid arthritis, whereas the anti-mutated citrullinated vimentin (Anti-MCV) is another anti-citrullinated antibody that reacts with mutated citrullinated vimentin. Therefore, we aimed to assess the diagnostic value of anti-MCV antibodies in RA patients and their relation to disease activity. This study included 60 RA patients and 25 normal controls. The disease activity of RA patients was assessed by disease activity score (DAS-28). ELISA was used to test patients and controls for anti-MCV and anti-CCP. The level of anti-MCV was significantly higher among patients with RA compared to the control group (1.56 ± 0.56 vs. 1.20 ± 0.19 mol/l; P< 0.001). Anti-MCV at cut-off point of > 1.2 mol/l had 76% sensitivity and 100% specificity, with an overall diagnostic accuracy of 83.2% for diagnosing RA. Regarding early RA diagnosis, anti-MCV at the cut-off point was > 1.2 mol/l with 70% sensitivity and 100% specificity. For diagnosis of late RA, the cut-off point was > 1.2 mol/l, with 93.3% sensitivity and 100% specificity, whereas the overall diagnostic accuracy was 96.3%. In this study, patients with positive anti-CCP had a marginally higher level of anti-MCV compared to those with negative anti-CCP (1.64 ± 0.28 vs. 1.48 ± 0.73 mol/l; P= 0.29). We concluded that serum levels of Anti-MCV can be used as a diagnostic test in RA. The increased serum levels of Anti-MCV, demonstrated the importance of Anti-MCV as an independent serum marker in predicting the outcome of RA.

Interaction between Mesenchymal Stem Cells and the Immune System in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease that causes damage to joints. This review focuses on the possibility of influencing the disease through immunomodulation by mesenchymal stem cells (MSCs). There is an occurrence of rheumatoid factor and RA-specific autoantibodies to citrullinated proteins in most patients. Citrulline proteins have been identified in the joints of RA patients, and are considered to be the most suitable candidates for the stimulation of anti-citrulline protein antibodies production. Fibroblast-like proliferating active synoviocytes actively promote inflammation and destruction in the RA joint, in association with pro-inflammatory cells. The inflammatory process may be suppressed by MSCs, which are a population of adherent cells with the following characteristic phenotype: CD105+, CD73+, CD90+, CD45−, CD34− and HLA DR−. Following the stimulation process, MSCs are capable of immunomodulatory action through the release of bioactive molecules, as well as direct contact with the cells of the immune system. Furthermore, MSCs show the ability to suppress natural killer cell activation and dendritic cells maturation, inhibit T cell proliferation and function, and induce T regulatory cell formation. MSCs produce factors that suppress inflammatory processes, such as PGE2, TGF-β, HLA-G5, IDO, and IL-10. These properties suggest that MSCs may affect and suppress the excessive inflammation that occurs in RA. The effect of MSCs on rheumatoid arthritis has been proven to be a suitable alternative treatment thanks to successful experiments and clinical studies.

Association between anti-P. gingivalis antibodies and anti-citrullinated vimentin antibodies in the patients with rheumatoid arthritis.

Abstract Objectives Anti-citrullinated-protein auto-antibodies (ACPA), especially that react to citrullinated vimentin (CV), are implicated in the pathogenesis of Rheumatoid arthritis (RA). P. gingivalis (Pg), a key pathogen of periodontitis, can citrullinate the host proteins by production of Pg-derived peptidylarginine deiminase (PPAD). This study evaluated the relationship among antibodies (Abs) that react cyclic citrullinated protein (CCP), CV and periodontal pathogens in the serum of RA patients or control subjects. Methods Blood serum of healthy subjects (n=10) and RA patients (n=26) were obtained from Precision for Medicine. Six distinctive peptide sequences of Vimentin (#1–#6) and corresponding CV (#1’–#6’) peptides were synthesized. ELISA was employed to detect IgG Ab titers for CCP, intact vimentin and CV peptides. Fixed periodontal pathogens, Pg 33277, F. nucleatum, P. intermedia, A. actinomycetemcomitans (Aa) Y4, S. mitis, S. gordonii, A. odontolyticus, and C. gingivalis were also used as IgG ELISA antigens. Results The levels of anti-CCP Ab were higher in RA patients with anti-Pg Ab than those without anti-Pg Ab. Since elevated anti-Pg Ab is hallmark of periodontitis, it is conceivable that RA patients with anti-Pg Ab would have periodontitis. However, there was no association between anti-CCP Ab and the Abs reactive to the other bacteria. Very interestingly, RA patients with anti-Pg Ab, but not those without anti-Pg Ab, showed significantly elevated Ab response to #6’ CV peptide compared to intact #6 vimentin peptide, among six peptide sequences tested. Conclusions Our findings indicated that periodontitis may be associated with the induction of ACPA via PPAD-mediated citrullination of host proteins. Supported by NIH NIDCR grants, DE-027851, DE-028715 and DE-331851

Rheumatoid Arthritis, Its Diagnostic Approach and How to treat it

Introduction. Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease characterized by symmetrical erosive polyarthritis leading to progressive disability. It is more common in women, with a 3:1 ratio. Environmental risk factors are smoking, exposure to silica and textile dust. Materials and methods. Fifteen articles and three books on rheumatoid arthritis were chosen to identify the most accurate diagnostic methods and the most effective and innovative treatments. Discussion. Related autoantibodies, such as rheumatoid factors, anti-citrullinated antibodies and anti- caramylated antibodies can be found in serum long before the disease develops. The interaction between genetic and environmental factors causes a breakdown of immune tolerance and triggers systemic autoimmunity. It has been shown that the lungs, oral mucosa, and gastrointestinal tract are initial sites where the immune system can become activated and produce RA. Different imaging techniques are available for diagnosis: plain radiography, Doppler ultrasound, and magnetic resonance imaging. Doppler ultrasound was found to be more sensitive in identifying minimal synovitis and more sensitive than plain radiography in detecting joint erosions. As pharmacological treatment, it has been concluded that the first-line drug is methotrexate, as it relieves signs and symptoms, improves physical function, and prevents or slows the progression of joint damage. We also observed that NSAIDs help in the inflammatory and symptomatic control of RA. Conclusion. The quality of life of affected patients has been maintained thanks to the early detection of the disease, since there are several treatments (physical therapies, aerobic exercises, medications, etc.), which help to stop the evolution of this disease and thus allow the patient to lead a daily life.

Characterization of Monoclonal Antibodies Recognizing Citrulline-Modified Residues.

BackgroundCitrullination is a post-translational protein modification linked to the occurrence and development of a variety of diseases. The detection of citrullinated proteins is predominately based on antibody detection although currently available reagents demonstrate detection bias according to the environmental context of the citrullinated residues. This study aimed to develop improved antibody reagents capable of detecting citrullinated residues in proteins in an unbiased manner.MethodsBALB/c mice were sequentially immunized using citrulline conjugates with different carrier proteins, and specific monoclonal antibodies (mAbs) identified by primary screening using citrulline-conjugated proteins unrelated to the immunogen. Secondary screening was performed to identify mAbs whose reactivity could be specifically blocked by free citrulline, followed by identification and performance assessment.ResultsTwo mAbs, 22F1 and 30G2, specifically recognizing a single citrulline residue were screened from 22 mAbs reacting with citrulline conjugates. Compared with commercially available anti-citrulline antibodies (AB6464, AB100932 and MABN328), 22F1 and 30G2 demonstrated significantly higher reactivity as well as a broader detection spectrum against different citrullinated proteins. 22F1 and 30G2 also had higher specificity than commercial antibodies and overall better applicability to a range of different immunoassays.ConclusionTwo mAbs specifically recognizing a single citrulline residue were successfully produced, each possessing good specificity against different citrullinated proteins. The improved utility of these reagents is expected to make a strong contribution to protein citrullination-related research.

Ангиопатия при ревматоидном артрите

Актуальность. Среди всех болезней ревматологического профиля на долю ревматоидного артрита (РА) приходится 3 % случаев, причем численность таких больных растет. Для РА характерно системное поражение сосудов (ангиопатия), характеризующееся по международной Чэпел-Хиллской классификации как «васкулит, связанный с системным заболеванием». Цель работы: улучшить качество диагностики, установить новые звенья патогенеза и выделить прогностические критерии течения поражения сосудов при РА. Материалы и методы. Под наблюдением находился 131 больной РА. Соотношение мужчин и женщин составило 1 : 2, минимальная, умеренная и высокая степени активности заболевания — соответственно 1 : 2 : 1, средний возраст обследованных пациентов составил 45,70 ± 1,02 года, длительность клинической манифестации — 9,40 ± 0,68 года, I, II, III и IV стадии диагностированы у 8, 40, 34 и 19 % от числа больных соответственно. Выполняли эхокардиографию, сонографию и ультразвуковую допплерографию сосудов, биомикроскопию конъюнктивы, морфологическое исследование нефробиоптатов, определяли интегральные индексы клинической и инструментальной сосудистой патологии. Результаты. Системная ангиопатия наблюдалась у 61 % от числа больных РА, чаще в случаях высокой степени активности при наличии остеопороза, при этом развитие васкулита кожи и периферической вазонейропатии было тесно связано с уровнем в сыворотке крови антител к циклическому цитруллиновому пептиду, который, наряду с концентрацией С-реактивного протеина, обладает негативной прогностической значимостью в отношении сосудистой патологии. Появление дигитального артериита определяется активностью суставного синдрома, гломерулонефрита — высоким содержанием в крови циркулирующих иммунных комплексов, а наличие ангиопатии отражает повышение давления в малом круге кровообращения. Выводы. У больных РА развивается мезангиопролиферативный или мезангиокапиллярный гломерулонефрит в соотношении 2 : 1 с закономерным тубулоинтерстициальным компонентом и депозицией иммуноглобулинов и компонентов комплемента (в строме → клубочках → канальцах → сосудах), при этом структурные изменения сосудов почек тесно связаны с клинико-инструментальными проявлениями системной ревматоидной ангиопатии. Показатели в крови C-реактивного протеина более 25 мг/л и противоцитруллиновых антител более 40 Е/мл являются прогнознегативными критериями в отношении системной сосудистой патологии и повреждений стромы почек, а тяжелые изменения почечных канальцев относятся к факторам риска высоких темпов прогрессирования суставного синдрома.

Altered Antibody Response to Epstein-Barr Virus in Patients With Rheumatoid Arthritis and Healthy Subjects Predisposed to the Disease. A Twin Study.

Objectives: To study Epstein-Barr virus (EBV) antibody patterns in twin individuals with rheumatoid arthritis (RA) and their healthy co-twins, and to determine the heritability of antibody responses against the EBV encoded EBNA1 protein.Methods: Isotypes of EBNA1 antibodies were measured in 137 RA affected- and 150 healthy twin pairs. We estimated the effect of RA and RA predisposition, anti-citrullinated antibodies (ACPA), IgM rheumatoid factor (RF), the shared epitope (SE) and the PTPN22-T allele (PTPN22) on the level of EBNA1 antibodies. We also determined the heritability of EBNA1 antibody levels.Results: IgA-EBNA1 antibody levels were increased in twins from RA discordant twin pairs irrespective of RA, ACPA or IgM-RF status. The IgG-EBNA1 antibody level was elevated in healthy co-twins from RA discordant twin pairs but not in RA affected twins. The IgM-EBNA1 antibody level was elevated in both RA twins and their healthy co-twins. The effect of RA on the IgA-EBNA1 antibody level was reversed when SE was present and with no effect of PTPN22. The heritability of IgA-, IgG- and IgM-EBNA1 antibody level was 40.6, 65.5, and 54.3%, with no effect of environment shared by the twins.Conclusion: EBNA1 antibody levels are distinctively different between patients with RA and healthy subjects but also between relatives of RA strongly predisposed to RA and healthy subjects. The high level of IgA EBNA1 antibodies associated with RA and a family predisposition to RA is attributable to both genetics incl. the shared epitope and environmental variation.