Citrullinated Protein Antibodies Research Articles

Inflammatory Arthritis in Systemic Sclerosis: Its Epidemiology, Associations, and Morbidity.

To describe the epidemiology, associations, and impact of inflammatory arthritis (IA) in systemic sclerosis (SSc). Patients with SSc prospectively enrolled in the Australian Scleroderma Cohort Study were included. IA was defined clinically as the presence of synovitis on examination. Logistic regression was used to determine the associations of IA with SSc manifestations and serological parameters. Patient-reported outcome measures were used to capture physical function and health-related quality of life (HRQoL). IA was a common SSc manifestation affecting one-third (33.3%) of patients over a median follow-up of 4.3 (1.7-8.4) years. Associations of IA included diffuse SSc (odds ratio [OR] 1.33, 95% confidence interval [95% CI] 1.01-1.74, P = 0.042), concurrent musculoskeletal manifestations (joint contractures and tendon friction rubs, OR 1.70, 95% CI 1.34-2.15, P < 0.001); myositis (OR 2.11, 95% CI 1.39-3.20, P < 0.001), and sicca symptoms (OR 1.57, 95% CI 1.14-2.16, P = 0.006), whereas IA was negatively associated with pulmonary arterial hypertension (OR 0.52, 95% CI 0.35-0.78, P = 0.002). Neither the presence of rheumatoid factor nor U1 small nuclear RNP were associated with IA (OR 1.13, 95% CI 0.88-1.44, P = 0.331, OR 1.46, 95% CI 0.89-2.39, P = 0.129 respectively). Positive anticyclic citrullinated protein antibodies, although at low frequency, were more common in those with IA compared with those without IA (7.5% vs 1.5%, P < 0.001). IA was associated with significantly lower HRQoL score (P < 0.001) and more physical disability than in those without IA (P < 0.001). IA is a common disease manifestation that is more frquently seen in diffuse disease. IA is associated with poor HRQoL and physical disability. Further research is needed into the effective management of IA in SSc.

Rheumatoid arthritis and the proinflammatory cytokine IL-17.

Rheumatoid arthritis (RA) is the most common inflammatory joint disease. Various proinflammatory cytokines are involved in the pathogenesis of this chronic disorder. It is characterized by the presence of autoantibodies, such as rheumatoid factor and antibodies against citrullinated peptides. The present study focuses on investigation of possible association between the proinflammatory cytokine interleukin 17 and anti-CCP, anti-MCV, and anti-CarP antibodies seropositivity in RA patients. To assess serum levels of interleukin 17 (IL-17) in patients with rheumatoid arthritis and healthy controls (HC) and to investigate the relationship between IL-17 and anti-cyclic citrullinated protein (anti-CCP) antibodies, antimutated citrullinated vimentin (anti-MCV) antibodies, and anti-carbamylated protein (anti-CarP) antibodies in patients with RA. Forty-seven patients diagnosed with rheumatoid arthritis and 44 healthy controls were included in the study. Serum IL-17 levels were examined in all participants. Anti-CCP, anti-MCV, and anti-CarP antibodies were tested in the group of RA patients. The mean serum level of IL-17 in RA patients was higher (12.8pg/ml) than that in healthy controls (7.9pg/ml), but the difference was not statistically significant (p=0.276). No significant correlation was observed between anti-CCP (+/-) and IL-17 (rs=0.162, p=0.380), and between anti-MCV (+/-) and IL-17 (rs=0.157, p=0.340). A significant positive correlation of moderate value was reported between anti-CarP (+/-) and IL-17 (rs=0.388, p=0.015). The present study demonstrated that the IL-17 serum levels in RA patients were increased compared to healthy controls. No correlation was found between ACPA immunological markers and IL-17 levels in patients with RA. A positive correlation was found between anti-CarP antibodies and IL-17 in the patients' group. The increased level of IL-17 is suggestive of its possible role in the pathogenesis of CarP positive RA patients.

Impact of Primary Hypothyroidism on Rheumatoid Arthritis Patients

Background: Rheumatoid arthritis is a systemic inflammatory disease with unknown etiology. There has been considerable debate about the relation between thyroid gland and rheumatic diseases.&#x0D; Objective: To assessed the prevalence of primary hypothyroidism in patients with rheumatoid arthritis, as well as the association between hypothyroidism and the severity of rheumatoid arthritis.&#x0D; Patients and Methods: This study is a cross-sectional observational study involving 65 participants 18 years of age and older who were diagnosed with RA. Patients had thyroid function tests and patient disease activity was determined using the DAS28 Modified Disease Activity Score .the data were analyzed using the chi-square significance test with a P-value of ≤0.05. The data will be collected during the direct patient interview and the information from the questionnaire once verbal approval has been received from the study participant.&#x0D; Results: Hypothyroidism (thyroid stimulating hormone) level &gt;4.20 µIU/L ) was observed in 26 (40%) parameters of disease activity such as DAS-28, counts tender joints significantly associated with hypothyroid patients RA.&#x0D; Conclusion: Hypothyroidism was significantly associated with disease severity of RA, disease duration, BMI (Body Mass Index), and ACPA (Anti Citrullinated Protein Antibody). Identification of thyroid function tests in patients with RA is important.

Impact of Primary Hypothyroidism on Rheumatoid Arthritis Patients

Background: Rheumatoid arthritis is a systemic inflammatory disease with unknown etiology. There has been considerable debate about the relation between thyroid gland and rheumatic diseases. Objective: To assessed the prevalence of primary hypothyroidism in patients with rheumatoid arthritis, as well as the association between hypothyroidism and the severity of rheumatoid arthritis. Patients and Methods: This study is a cross-sectional observational study involving 65 participants 18 years of age and older who were diagnosed with RA. Patients had thyroid function tests and patient disease activity was determined using the DAS28 Modified Disease Activity Score .the data were analyzed using the chi-square significance test with a P-value of ≤0.05. The data will be collected during the direct patient interview and the information from the questionnaire once verbal approval has been received from the study participant. Results: Hypothyroidism (thyroid stimulating hormone) level &gt;4.20 µIU/L ) was observed in 26 (40%) parameters of disease activity such as DAS-28, counts tender joints significantly associated with hypothyroid patients RA. Conclusion: Hypothyroidism was significantly associated with disease severity of RA, disease duration, BMI (Body Mass Index), and ACPA (Anti Citrullinated Protein Antibody). Identification of thyroid function tests in patients with RA is important. Keywords: Rheumatoid arthritis, hypo-thyrodism, rheumatoid arthritis activity

Combination of Two Monoclonal Anti-Citrullinated Protein Antibodies Induced Tenosynovitis, Pain, and Bone Loss in Mice in a Peptidyl Arginine Deiminase-4-Dependent Manner.

The appearance of anti-citrullinated protein antibodies (ACPAs) in the circulation represents a major risk factor for developing rheumatoid arthritis (RA). Patient-derived ACPAs have been shown to induce pain and bone erosion in mice, suggesting an active role in the pathogenicity of RA. We undertook this study to investigate whether ACPAs can induce tenosynovitis, an early sign of RA, in addition to pain and bone loss and whether these symptoms are dependent on peptidyl arginine deiminase 4 (PAD4). Monoclonal ACPAs generated from plasma cells of RA patients were transferred to wild-type and PAD4-deficient mice. Pain-like behavior and macroscopic inflammation were monitored for a period of 4 weeks, followed by the analyses of tenosynovitis in the ankle joints using magnetic resonance imaging (MRI) and bone microarchitecture in the tibia using an X-ray microscope. Microscopic changes in the tendon sheath were analyzed in decalcified ankle joint sections. The combination of 2 monoclonal ACPAs (1325:04C03 and 1325:01B09) induced long-lasting pain-like behavior and trabecular bone loss in mice. Although no synovitis was observed macroscopically, we detected tenosynovitis in the ACPA-injected mice by MRI. Microscopic analyses of the joints revealed a cellular hyperplasia and a consequent enlargement of the tendon sheath in the ACPA-treated group. In PAD4-/- mice, the effects of ACPAs on pain-like behavior, tenosynovitis, and bone loss were significantly reduced. Monoclonal ACPAs can induce tenosynovitis in addition to pain and bone loss via mechanisms dependent on PAD4-mediated citrullination.

Intermetatarsal Bursitis, a Novel Feature of Juxtaarticular Inflammation in Early Rheumatoid Arthritis Related to Clinical Signs: Results of a Longitudinal Magnetic Resonance Imaging Study.

Intermetatarsal bursae in the forefeet possess a synovial lining similar to joints and tendon sheaths. Inflammation of these bursae (intermetatarsal bursitis [IMB]) was recently identified as specific for early rheumatoid arthritis (RA). The present study was undertaken to determine if IMB is indeed an RA feature by assessing the following: 1) the association with other local inflammatory measures (synovitis, tenosynovitis, and osteitis), 2) the association with clinical signs, and 3) whether it responds to disease-modifying antirheumatic drug (DMARD) therapy similarly to other local inflammatory measures. One hundred fifty-seven consecutive early RA patients underwent unilateral contrast-enhanced 1.5T forefoot magnetic resonance imaging (MRI) at diagnosis. MRIs were evaluated for IMB presence and for synovitis, tenosynovitis, and osteitis in line with the RA MRI Scoring (RAMRIS) system (summed as RAMRIS inflammation). MRIs at 4, 12, and 24 months were evaluated for IMB presence and size in patients who had IMB at baseline and received early DMARD therapy. Logistic regression and generalized estimating equations were used. Anti-citrullinated protein antibody (ACPA) stratification was performed. Sixty-nine percent of RA patients had ≥1 IMB. In multivariable analysis on bursa level, presence of IMB was independently associated with local presence of synovitis and tenosynovitis, with odds ratios (OR) of 1.69 (95% confidence interval [95% CI] 1.12, 2.57) and 2.83 (95% CI 1.80, 4.44), respectively, but not osteitis. On the patient level, IMB presence was most strongly associated with tenosynovitis (OR 2.92 [95% CI 1.62, 5.24]). IMB presence was associated with local joint swelling (OR 2.7 [95% CI 1.3, 5.3]) and tenderness (OR 1.7 [95% CI 1.04, 2.9]) independent of RAMRIS inflammation. During treatment, IMB size decreased between 0 and 12 months. This decrease associated with decrease in RAMRIS inflammation, which was driven by synovitis decrease. Within ACPA-positive and ACPA-negative RA, similar results were obtained. IMB particularly accompanies inflammation of the synovial lining of joints and tendon sheaths, showed a similar treatment response after DMARD initiation, and associates with typical clinical signs. These findings suggest that IMB represents a frequently present novel RA feature of juxtaarticular synovial inflammation.

How RA Associated HLA-DR Molecules Contribute to the Development of Antibodies to Citrullinated Proteins: The Hapten Carrier Model.

The risk to develop ACPA positive rheumatoid arthritis (RA), the most destructive type of autoimmune arthritis, is carried by HLA-DRB1 alleles containing a 5 amino acid motif: the shared epitope (SE). RA is preceded by the emergence of disease specific anti citrullinated protein antibodies (ACPA). SE positive HLA-DRB1 alleles are associated with ACPA and ACPA positive RA, not with ACPA negative RA, suggesting that ACPA contribute to the pathogenesis of RA. Understanding how HLA-DRB1 genotypes influence ACPA could lead to a curative or preventive treatment of RA. The “Shared epitope binds citrullinated peptides “ hypothesis suggests that RA associated HLA-DR alleles present citrullinated peptides to T cells that help ACPA producing B cells. The “Hapten carrier model” suggests that PAD4 is the target of the T cells which help ACPA specific B cells through a hapten carrier mechanism in which PAD4 is the carrier and citrullinated peptides are the haptens. Direct binding assay of citrullinated peptides to purified HLA-DR molecules does not support the “shared epitope binds citrullinated peptides” hypothesis. The Odds Ratios to develop ACPA positive RA associated with each of 12 common HLA-DRB1 genotypes match the probability that the two HLA-DR molecules they encode can bind at least one peptide from PAD4, not from citrullinated fibrinogen. Thus, PAD4 tolerization might stop the carrier effect and switch off production of ACPA.

IgG Anti-Citrullinated Protein Antibody Variable Domain Glycosylation Increases Before the Onset of Rheumatoid Arthritis and Stabilizes Thereafter: A Cross-Sectional Study Encompassing ~1,500 Samples.

ObjectiveThe autoimmune response in rheumatoid arthritis (RA) is marked by the presence of anti–citrullinated protein antibodies (ACPAs). A notable feature of IgG ACPA is the abundant expression of N‐linked glycans in the variable domain. However, the presence of ACPA variable domain glycosylation (VDG) across disease stages, and its response to therapy, are poorly described. To understand its dynamics, we investigated the abundance of IgG ACPA VDG in 1,498 samples from individuals in different clinical stages.MethodsUsing liquid chromatography, we analyzed IgG ACPA VDG profiles in 7 different cohorts from Japan, Canada, The Netherlands, and Sweden. We assessed 106 healthy individuals, 228 individuals with presymptomatic RA, 277 individuals with arthralgia, 307 patients with new‐onset/early RA, and 117 RA patients after prespecified treatment regimens. Additionally, we measured VDG in 234 samples from patients with RA who did or did not achieve long‐term drug‐free remission (DFR) during up to 16 years follow‐up.ResultsIgG ACPA VDG significantly increased (P < 0.0001) toward disease onset and was associated with ACPA levels and epitope spreading prior to diagnosis. A slight increase in VDG was observed in patients with established RA, with a moderate influence of treatment (P = 0.007). In patients in whom DFR was later achieved, IgG ACPA VDG was already reduced at the time of RA onset.ConclusionThe abundance of IgG ACPA VDG increases toward RA onset and correlates with maturation of the ACPA response. While IgG ACPA VDG levels are fairly stable in established disease, a lower degree of VDG at RA onset correlates with DFR. Although the underlying biologic mechanisms remain elusive, our data support the concept that VDG relates to an expansion of the ACPA response in the pre‐disease phase and contributes to disease development.

Accuracy and tolerability of self-sampling of capillary blood for analysis of inflammation and autoantibodies in rheumatoid arthritis patients—results from a randomized controlled trial

BackgroundRheumatoid arthritis (RA) requires early diagnosis and tight surveillance of disease activity. Remote self-collection of blood for the analysis of inflammation markers and autoantibodies could improve the monitoring of RA and facilitate the identification of individuals at-risk for RA.ObjectiveRandomized, controlled trial to evaluate the accuracy, feasibility, and acceptability of an upper arm self-sampling device (UA) and finger prick-test (FP) to measure capillary blood from RA patients for C-reactive protein (CRP) levels and the presence of IgM rheumatoid factor (RF IgM) and anti-cyclic citrullinated protein antibodies (anti-CCP IgG).MethodsRA patients were randomly assigned in a 1:1 ratio to self-collection of capillary blood via UA or FP. Venous blood sampling (VBS) was performed as a gold standard in both groups to assess the concordance of CRP levels as well as RF IgM and CCP IgG. General acceptability and pain during sampling were measured and compared between UA, FP, and VBS. The number of attempts for successful sampling, requests for assistance, volume, and duration of sample collection were also assessed.ResultsFifty seropositive RA patients were included. 49/50 (98%) patients were able to successfully collect capillary blood. The overall agreement between capillary and venous analyses for CRP (0.992), CCP IgG (0.984), and RF IgM (0.994) were good. In both groups, 4/25 (16%) needed a second attempt and 8/25 (32%) in the UA and 7/25 (28%) in the FP group requested assistance. Mean pain scores for capillary self-sampling (1.7/10 ± 1.1 (UA) and 1.9/10 ± 1.9 (FP)) were significantly lower on a numeric rating scale compared to venous blood collection (UA: 2.8/10 ± 1.7; FP: 2.1 ± 2.0) (p=0.003). UA patients were more likely to promote the use of capillary blood sampling (net promoter score: +28% vs. −20% for FP) and were more willing to perform blood collection at home (60% vs. 32% for FP).ConclusionsThese data show that self-sampling is accurate and feasible within one attempt by the majority of patients without assistance, allowing tight monitoring of RA disease activity as well as identifying individuals at-risk for RA. RA patients seem to prefer upper arm-based self-sampling to traditional finger pricking.Trial registrationDRKS.de Identifier: DRKS00023526. Registered on November 6, 2020.

Ability of α – II Spectrin Breakdown Products and Septin 5 as Predictors for Severity and Clinical Outcome in Rheumatoid Arthritis Patients

There is a continuous interesting in finding new biomarkers that can be used as diagnostic tools for severity of rheumatoid arthritis (RA). Septin-5, a protein that indirectly inhibit neurotransmitter release, Alpha-2 spectrin breakdown products 145 (SBDP145), a protein that increased in neuronal damage, and vitamin D (VitD) are measured in the sera of 120 RA patients and 60 healthy controls (HC). The results showed an increase in SBDP145 level and a decrease in the VitD and calcium levels in RA group compared to HC. While no significant difference in septin-5 and magnesium between the groups. The receiver operating characteristics study showed that VitD has a good sensitivity and specificity for differentiating RA from HC. While Septin-5 and SBDP145 have no significant sensitivity and specificity. There is an increase in the serum levels of erythrocyte sedimentation rate (ESR) and anticyclic citrullinated protein antibody (ACCPA) in RA patients compared with the control group. Also, there are high ratios of RA patients with positive results of C-reactive protein (CRP) and rheumatoid factor (RF). It can be concluded that RA patients are suffering from hypovitaminosis D and hypocalcemia.

The new onset seropositive rheumatoid arthritis after COVID-19 infection: coincidental or related

Coronavirus disease 2019 (COVID-19) is an infectious disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The relationship of COVID-19 with rheumatological disorders has been researched since 2019. Rheumatoid arthritis (RA) is one of the most common rheumatoid diseases. The relationship between RA and COVID-19 is particularly interesting due to common cytokines in etiopathogenesis. SARS-CoV-2 was involved in triggering RF-positive and ACPA-positive arthritis, which might be diagnosed as rheumatoid arthritis, but we cannot rule out the possibility that the onset of this arthritis could have been coincidental. We report the case who has the first flare of RA with a high titer of Rheumatoid Factor (RF) and Anti Citrullinated Protein Antibody (ACPA) after mild SARS-CoV- 2 infection.

Association of Polygenic Risk Scores With Radiographic Progression in Patients With Rheumatoid Arthritis.

To investigate whether polygenic risk scores obtained using data from a genome-wide association study (GWAS) of rheumatoid arthritis (RA) susceptibility can be predictors of radiographic progression. We constructed polygenic risk scores using GWAS summary data on associations of single-nucleotide polymorphisms with RA susceptibility. The polygenic risk scores were stratified into quintiles based on levels of significance (ranging from top quintile of polygenic risk scores to bottom quintile). In addition, change in the Sharp/van der Heijde score (SHS) of radiographic progression over the first 5 years after onset of RA was assessed. The change in SHS over 5 years was stratified according to quartiles, with the top quartile of change in SHS defined as severe radiographic progression (score change of >35 points) and the remaining 3 quartiles defined as nonsevere radiographic progression. Polygenic risk scores were assessed for their ability to predict the SHS status over 5 years in a training set (n = 500 RA patients) for selection of the best model, and in a testing set (n = 740 RA patients) for validation of the data. We evaluated the performance of the polygenic risk score as a predictor of severe radiographic progression in univariable and multivariable analyses with inclusion of other factors. Polygenic risk scores constructed from 43,784 single-nucleotide polymorphisms significantly differed between patients who experienced severe radiographic progression and those with nonsevere radiographic progression in both the training set (P = 0.0064) and the testing set (P = 0.017). Patients with polygenic risk scores in the top quintile had a higher risk of severe progression compared to those with polygenic risk scores in the bottom quintile (odds ratio [OR] 1.90, P = 0.0022), and the risk of severe radiographic progression was even higher when restricted to patients who were younger at disease onset (OR 5.06, P = 0.00038). The group with polygenic risk scores in the top quintile and the anti-citrullinated protein antibody (ACPA)-positive group had significantly higher proportions of patients with severe radiographic progression (P = 0.00052 and P = 0.0022, respectively) compared to the remaining groups. Multivariable analysis showed that polygenic risk score (P = 0.00019) as well as female sex (P = 0.0033), ACPA positivity (P = 0.0023), and body mass index (P = 0.024) were independent risk factors for severe radiographic progression. A polygenic risk score that is derived from GWAS data on RA susceptibility is associated with the level of severity of radiographic progression in patients with RA.

Amidst the chaos of late rheumatoid arthritis with no treatment

A 78-year-old man with 24 years history of Rheumatoid Arthritis (RA) came with neck pain. He always refused any treatment except for NSAIDs. From 2 years ago, he was bedridden. He was chronic cigarette smoker. On examination, he had rheumatoid nodules, severe both hands deformity, elbows flexion contracture and knee joints limitation of motion. His lab tests showed high titer of rheumatoid factor and anti cyclic citrullinated protein antibody, high ESR, CRP and vitamin D deficiency. Radiologic studies showed multiple vertebral osteoporotic fractures. Cervical spine CT scan (a and b) showed destruction of the odontoid process and fusion of facet joints of the C2, C3 and C4. MRI of cervical spine (c) showed destruction of odontoid process surrounding by inflammatory synovitis. CT scan of lung (e and f) showed multiple upper lobeand sub pleural nodules along fibrotic changes in base of right lobe. X-ray of knee and hip (d and g) showed severe osteoarthritis andsite of previouship nailing. The patient was diagnosed with advanced erosive nodular RA, severe secondary osteoporosis, osteoarthritis and rheumatoid lung. Standard treatment was recommended, although he again refused. RA can result in progressive joint destruction, deformity and disability [1]. In the spine, it has a predilection for the cervical area, leads to odontoid erosion, spinal instability, and subluxation. In the era of importance of early treatment, these complications are rarely seen, however despite biologic therapy, it has been shown that 15-30% of RA patients can still have preclinical cervical spine abnormalities [2]. The Osteoporosis (OP) is more frequent in patients with high disease activity, bone erosions, &gt;10 years disease duration, and high titers of anti-CCP and RF positivity [3]. Our patient with multiple poor prognostic factors for erosive RA came with extra articular and complications of this disease due refusing treatment.

The Effects of Non-Surgical Periodontitis Therapy on the Clinical Features and Serological Parameters of Patients Suffering from Rheumatoid Arthritis as Well as Chronic Periodontitis.

ObjectiveThe present study aims to evaluate the effects of basic periodontal disease therapy on the general condition and serum inflammatory indicators of patients with rheumatoid arthritis (RA) combined with chronic periodontitis (CP).MethodsForty patients with RA were enrolled in the study and, based on the results of an oral examination and in line with the 2018 periodontitis diagnostic criteria, they were divided into a group with CP (the RA + CP group) and a group without CP (the RA group). Twenty-nine patients with CP who attended the periodontal department of our hospital were recruited as a group with only CP (the CP group), and 20 volunteers without any systemic or periodontal disease were recruited as a healthy control group (the H group). The periodontal and joint conditions of the subjects in the four groups were recorded; anti-cyclic citrullinated protein antibodies, interleukin 6 (IL-6), C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and rheumatoid factor levels, which reflect the severity of the RA, were detected, and the differences between the groups were analyzed. The probing depth (PD), clinical attachment loss, and sulcus bleeding index (SBI), which reflect the severity of the periodontitis, were correlated with the factor levels. The RA + CP and CP groups received therapeutic intervention, and the differences in each indicator before and six weeks after the treatment were compared, and their data were compared with those of patients in the RA group and H groups.ResultsCompared with the RA group, the serum expressions of ESR, CRP, and IL-6 were significantly higher in the RA + CP group. There were significant differences in the levels of PD, SBI, IL-6, and CRP in the patients receiving basic periodontal disease therapy before and after the treatment.ConclusionA relatively large proportion of patients with RA have chronic periodontitis, and the local inflammatory state of CP might exacerbate the systemic inflammatory response in RA. Basic periodontal disease therapy may improve the oral condition of patients with RA and reduce the serum levels of the inflammatory factors.

Sunlight Exposure, Sun-Protective Behavior, and Anti-Citrullinated Protein Antibody Positivity: A General Population-Based Study in Quebec, Canada.

To examine associations between sunlight exposure and anti-citrullinated protein antibodies (ACPAs) using general population data in Quebec, Canada. A random sample of 7,600 individuals (including 786 subjects who were ACPA positive and 201 self-reported rheumatoid arthritis [RA] cases) from the CARTaGENE cohort was studied cross-sectionally. All subjects were nested in 4 census metropolitan areas, and mixed-effects logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) for ACPA positivity related to sunlight exposure, adjusting for sun-block use, industrial fine particulate matter (PM2.5 ) exposures, smoking, age, sex, French Canadian ancestry, and family income. We also performed sensitivity analyses excluding subjects with RA, defining ACPA positivity by higher titers, and stratifying by age and sex. The adjusted ORs and 95% CIs did not suggest conclusive associations between ACPA and sunlight exposure or sun-block use, but robust positive relationships were observed between industrial PM2.5 emissions and ACPA (OR 1.19 per μg/m3 [95% CI 1.03-1.36] in primary analyses). We did not see clear links between ACPA and sunlight exposure or sun-block use, but we did note positive associations with industrial PM2.5 . Future studies of sunlight and RA (or ACPA) should take air pollution exposures into account.

Association of Sputum Neutrophil Extracellular Trap Subsets With IgA Anti–Citrullinated Protein Antibodies in Subjects at Risk for Rheumatoid Arthritis

ObjectiveMechanisms leading to anti–citrullinated protein antibody (ACPA) generation in rheumatoid arthritis (RA) are hypothesized to originate in the lung. We undertook this study to understand associations between neutrophil extracellular trap (NET) formation in the lung and local ACPA generation in subjects at risk of developing RA.MethodsInduced sputum was collected from 49 subjects at risk of developing RA, 12 patients with RA, and 18 controls. Sputum neutrophils were tested for ex vivo NET formation, and sputum‐induced NET formation of control neutrophils was measured using immunofluorescence imaging. Sputum macrophages were tested for ex vivo endocytosis of apoptotic and opsonized cells. Levels of ACPA, NET remnants, and inflammatory proteins were quantified in sputum supernatant.ResultsSpontaneous citrullinated histone H3 (Cit‐H3)–expressing NET formation was higher in sputum neutrophils from at‐risk subjects and RA patients compared to controls (median 12%, 22%, and 0%, respectively; P < 0.01). In at‐risk subjects, sputum IgA ACPA correlated with the percentage of neutrophils that underwent Cit‐H3+ NET formation (r = 0.49, P = 0.002) and levels of Cit‐H3+ NET remnants (r = 0.70, P < 0.001). Reduced endocytic capacity of sputum macrophages was found in at‐risk subjects and RA patients compared to controls. Using a mediation model, we found that sputum inflammatory proteins were associated with sputum IgA ACPA through a pathway mediated by Cit‐H3+ NET remnants. Sputum‐induced Cit‐H3+ NET formation also correlated with sputum levels of interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor in at‐risk subjects, suggesting a causal relationship.ConclusionThese data support a potential mechanism for mucosal ACPA generation in subjects at risk of developing RA, whereby inflammation leads to increased citrullinated protein–expressing NETs that promote local ACPA generation.

The Interleukin-1 Receptor-Associated Kinase 4 Inhibitor PF-06650833 Blocks Inflammation in Preclinical Models of Rheumatic Disease and in Humans Enrolled in a Randomized Clinical Trial.

ObjectiveTo investigate the role of PF‐06650833, a highly potent and selective small‐molecule inhibitor of interleukin‐1–associated kinase 4 (IRAK4), in autoimmune pathophysiology in vitro, in vivo, and in the clinical setting.MethodsRheumatoid arthritis (RA) inflammatory pathophysiology was modeled in vitro through 1) stimulation of primary human macrophages with anti–citrullinated protein antibody immune complexes (ICs), 2) RA fibroblast‐like synoviocyte (FLS) cultures stimulated with Toll‐like receptor (TLR) ligands, as well as 3) additional human primary cell cocultures exposed to inflammatory stimuli. Systemic lupus erythematosus (SLE) pathophysiology was simulated in human neutrophils, dendritic cells, B cells, and peripheral blood mononuclear cells stimulated with TLR ligands and SLE patient ICs. PF‐06650833 was evaluated in vivo in the rat collagen‐induced arthritis (CIA) model and the mouse pristane‐induced and MRL/lpr models of lupus. Finally, RNA sequencing data generated with whole blood samples from a phase I multiple‐ascending‐dose clinical trial of PF‐06650833 were used to test in vivo human pharmacology.ResultsIn vitro, PF‐06650833 inhibited human primary cell inflammatory responses to physiologically relevant stimuli generated with RA and SLE patient plasma. In vivo, PF‐06650833 reduced circulating autoantibody levels in the pristane‐induced and MRL/lpr murine models of lupus and protected against CIA in rats. In a phase I clinical trial (NCT02485769), PF‐06650833 demonstrated in vivo pharmacologic action pertinent to SLE by reducing whole blood interferon gene signature expression in healthy volunteers.ConclusionThese data demonstrate that inhibition of IRAK4 kinase activity can reduce levels of inflammation markers in humans and provide confidence in the rationale for clinical development of IRAK4 inhibitors for rheumatologic indications.

Bone-sparing effects of rituximab and body composition analysis in a cohort of postmenopausal women affected by rheumatoid arthritis - retrospective study.

ObjectiveOsteoporosis is the most common bone tissue disease and it is characterized by a reduced bone mineral density (BMD). The main physiopathological mechanisms converge on the uncoupling between bone formation and resorption, thus leading to an enhanced risk of fractures. Several papers have documented the inverse relationships linking high inflammatory cytokines, anti-citrullinated protein antibodies, rheumatoid factor, and BMD in rheumatoid arthritis (RA). Rituximab (RTX) is a chimeric monoclonal antibody directed against the CD20 receptor of B cells. Since the Food and Drug Administration approved it for RA in 2006, there have been many clinical experiences regarding its use. Nevertheless, few studies evaluate the effect of rituximab on BMD. RA is a disease characterized by immune dysfunction with high levels of inflammatory cytokines, autoantibodies, and it is reasonable that a B cell depleting therapy could restore a physiological cytokine balance, thus exerting an osteoprotective effect on the bone tissue. The purpose of this paper is to highlight any difference in BMD and to assess differences in body composition over a retrospective 18-month follow-up period after RTX treatment with a B cell depleting therapy.Material and methodsWe analyzed by dual energy X-ray absorptiometry BMD expressed as g/cm2 and body composition modifications over 18 months with RTX treatment of 20 postmenopausal RA patients.ResultsAfter eighteen months of therapy with RTX, a statistically significant increase in vertebral (L1–L4) BMD and the stability of femoral BMD were documented.ConclusionsRituximab is associated with an improvement of vertebral and preservation of femoral BMD, suggesting a bone-sparing effect due to B cell depletion. Furthermore, patients displayed a redistribution of fat masses toward the hip region.

Immunopathogenesis and Immunotherapeutic Strategies in Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a systemic autoimmune disease which results from failure of immune tolerance. Autoantibodies like Rheumatoid factor, Anti-Carbamylated Antibodies, Anti-Acetylated and Anti- Citrullinated Protein Antibodies keep on circulating in blood which target self-tissues. The major symptoms of RA are polyarticular inflammation of the synovial membrane, wrists and feet along with the joint tenderness and formation of nodules in the joints. There are many MHC alleles as well as non-MHC immunoregulatory genes which confer the genetic risk in Rheumatoid Arthritis. Immunotherapeutic strategies involved are dendritic cell targeted therapeutics, cell-based therapy and autoantibody-mediated refractoriness. The increase in the mortality rate of RA is recognized widely but different aspects of immunopathogenesis are not explained fully. The aim of the review article is to discuss all the factors that can contribute towards the immunopathogenesis of this disease and to screen out the most prominent immunotherapeutic strategies.

Combinations of Anticyclic Citrullinated Protein Antibody, Rheumatoid Factor, and Serum Calprotectin Positivity Are Associated With the Diagnosis of Rheumatoid Arthritis Within 3 Years.

ObjectiveTo evaluate the prevalence of elevations of anti‐cyclic citrullinated peptide‐3 (anti‐CCP3) antibody, rheumatoid factor IgM (RF‐IgM) and serum calprotectin (sCP) in pre–rheumatoid arthritis (RA) as well as the diagnostic accuracies of these biomarkers for the timing of diagnosis of future RA.MethodsA total of 215 RA cases, each with approximately three pre‐RA diagnoses and one post–RA diagnosis serum sample, and controls were identified from the Department of Defense Serum Repository. All case samples and a single sample from each control subject were tested for anti‐CCP3 (IgG), RF‐IgM, and sCP. The diagnostic accuracies of biomarkers for future RA were evaluated.ResultsAnti‐CCP3, RF‐IgM, and sCP were elevated in pre‐RA, with anti‐CCP3 and sCP significantly elevated compared with RF‐IgM at the earliest time points. Within the cases, the combination of anti‐CCP3 and RF‐IgM positivity had a positive predictive value (PPV) of 35.6% for a diagnosis of RA in 3 years or less, which is significantly higher than the PPV of 18.7% for anti‐CCP3 positivity alone (P < 0.001). A combination of anti‐CCP3, RF‐IgM, and sCP had the highest PPV (53.0%) for a diagnosis of RA in 3 years or less; however, this was not significantly higher than the PPV for anti‐CCP3 and RF‐IgM positivity (P = 0.248).ConclusionAnti‐CCP3, RF‐IgM, and sCP are elevated in pre‐RA; furthermore, combinations of elevations of these biomarkers are more commonly seen in the period of less than or equal to 3 years to diagnosis. This may be considered in creating inclusion criteria in prevention trials in RA. In addition, the biologic relationships of these biomarkers in pre‐RA need exploration.