Etiology and Pathogenesis of Rheumatoid Arthritis-Interstitial Lung Disease

Interstitial lung disease (ILD) is one of the most serious extra-articular complications of rheumatoid arthritis (RA), which increases the mortality of RA. Because the pathogenesis of RA-ILD remains poorly understood, appropriate therapeutic strategies and biomarkers have not yet been identified. Thus, the goal of this review was to summarize and analyze the reported data on the etiology and pathogenesis of RA-ILD. The incidence of RA-ILD increases with age, and is also generally higher in men than in women and in patients with specific genetic variations and ethnicity. Lifestyle factors associated with an increased risk of RA-ILD include smoking and exposure to pollutants. The presence of an anti-cyclic citrullinated peptide antibody, high RA disease activity, and rheumatoid factor positivity also increase the risk of RA-ILD. We also explored the roles of biological processes (e.g., fibroblast-myofibroblast transition, epithelial-mesenchymal transition, and immunological processes), signaling pathways (e.g., JAK/STAT and PI3K/Akt), and the histopathology of RA involved in RA-ILD pathogenesis based on published preclinical and clinical models of RA-ILD in animal and human studies.

Childhood-onset rheumatoid arthritis at a tertiary hospital in Senegal, West Africa

BACKGROUND

Childhood-onset rheumatoid arthritis (CORA), known as rheumatoid factor (RF)-positive juvenile idiopathic arthritis is a type of juvenile idiopathic arthritis that shares the same genetic factors and clinical features as adult-onset rheumatoid arthritis. In Africa, CORA hasn't been the subject of a specific study.

OBJECTIVES

The aim of this study is to describe the clinical features, disease activity, functional disability, and treatment of CORA at diagnosis in Senegal and compare the findings to other CORA populations.

METHODS

We conducted a mixed cohort study by reviewing the medical records of patients diagnosed with CORA with an age of symptom onset < 18 years according to the 2019 PRINTO provisional criteria for RF-positive JIA from January 2020 to December 2022 at rheumatology department of Aristide Le Dantec Hospital in Dakar, Senegal. We collected demographic, clinical, paraclinical and therapeutic data. Disease activity score was assessed by DAS28-ESR and DAS28-CRP. Functional disability was assessed using Health Assessment Questionnaire (HAQ) or Childhood HAQ.

RESULTS

A total of 21 patients were included. Eighteen (85.7%) were Females. The mean age at symptom onset was 13.0 ± 3.0 years, and at diagnosis was 16.4 ± 4.2 years. Morning stiffness, joint swelling, and joint deformities were found in 20, 18 and 13 patients respectively. Four patients had a family history of rheumatoid arthritis. Five patients had extra-articular involvement such as rheumatoid nodules. Two patients had interstitial lung disease. The biological inflammatory syndrome was found in 90% of cases. 16 of 21 (76.2%) patients had positive RF, and 18 of 20 (90%) patients had positive Anti-CCP. Seven of 12 (58.3%) patients had positive anti-nuclear antibodies. The mean DAS28-ESR was 5.7 ± 1.0. Fifteen (71.4%) patients had high disease activity (DAS28-ESR > 5.1). The mean DAS28-CRP was 5.4 ± 1.1. The median HAQ was 2.12 with a mean HAQ of 1.9. Nineteen (90.5%) patients were treated with methotrexate, while 17 (81%) had a combination of methotrexate and hydroxychloroquine. Oral prednisone was used in 17 (81%) cases. Non-steroidal anti-inflammatory drugs were used in 4 cases (19%). After 6 months of treatment, mean DAS28-CRP was 2.9.

CONCLUSION

In our study, CORA mainly affects 13-year-old girls, characterised by high disease activity with joint deformity and significant functional impairment. Treatment is mainly based on methotrexate, prednisone and hydroxychloroquine. Further studies are needed to determine the exact clinical phenotype of this disease.

A Monovalent Fab Affinity-Capture and Elution Bridging Immunoassay Overcomes Rheumatoid Factor Interference while Accurately Detecting Antidrug Antibodies

BACKGROUND

Rheumatoid factor (RF) consists of autoantibodies that bind the fragment crystallizable (Fc) region of human immunoglobulin G (IgG) and present in sera of rheumatoid arthritis (RA) patients. Immunoassays to detect antidrug antibodies (ADA) in RA patient samples may experience interference due to RF binding and crosslinking Fc regions of the capture and detection antibody reagents. To overcome this interference, a novel Fab affinity-capture and elution (ACE)-bridging immunoassay (Fab ACE-Bridge) was developed with monovalent-recombinant Fab to avoid RF interference.

METHODS

ACE and ACE-Bridge assays were developed to detect ADA against a therapeutic monoclonal antibody using samples from healthy donors, psoriasis patients, and RA patients. The performance of these assays was compared to a novel Fab ACE-Bridge assay, in which monoclonal antibody was replaced with monovalent Fab.

RESULTS

High screening signals in the ACE and ACE-Bridge assays were detected in RA patient samples but not in samples from healthy donors or psoriasis patients. The high screening signals in RA samples did not inhibit to the expected extent in the confirmatory assay, a consistent feature of false-positive screening results. Further investigation revealed RF as the interferent affecting assay performance. Modification of the ACE-Bridge assay by using monovalent Fab eliminated RF interference while allowing for sensitive and drug-tolerant detection of authentic ADA.

CONCLUSIONS

RF interfered significantly in traditional ACE and ACE-Bridge assays. Implementation of a novel monovalent Fab ACE-Bridge assay overcame RF interference. The use of monovalent Fab is recommended for immunogenicity assays when assessing ADA in RA patient samples.

Rheumatoid factor recognizes specific domains of the IgG heavy chain complexed with HLA class II molecules

OBJECTIVE

We previously reported that RF recognized the IgG heavy chain (IgGH)/RA-susceptible HLA class II molecule complex. In the present study, we investigated the molecular mechanisms underlying HLA binding to and the RF recognition of IgGH.

METHODS

We synthesized various types of IgGH segments, including VH, CH1, CH2 and CH3, and transfected them with or without HLA class II molecules into the Human Embryonic Kidney 293T cell line. IgGH single domains linked with the HLA-Cw3 peptide, which binds to the binding groove of the HLA class II molecule, were also synthesized. The expression of IgGH domains on the cell surface and their recognition by RF were examined using flow cytometry.

RESULTS

Flag-tagged IgGH segments containing CH1 (CH1, VH-CH1, CH1-CH2, VH-CH1-CH2, CH1-CH2-CH3 and VH-CH1-CH2-CH3) were clearly presented on the cell surface by HLA-DR4, while segments without the CH1 domain were expressed at a low level, and the CH3 single domain was only weakly detected on the cell surface, even with HLA-DR4. We then transfected IgGH single domains linked to the Cw3 peptide together with HLA-DR4 and showed that RF-containing sera from RA patients only recognized the CH3 domain and none of the other single domains. When various segments without the Cw3 peptide were transfected with HLA-DR4, only the CH1-CH2-CH3 segment and full-length IgGH were detected by the sera of RA patients.

CONCLUSION

The CH1 domain of IgGH binds to the RA-susceptible HLA-DR molecule and is expressed on the cell surface. RF specifically recognizes the CH3 domain of the IgGH/HLA-DR4 complex.

The Symptoms in Persons At Risk of Rheumatoid Arthritis (SPARRA) questionnaire: predicting clinical arthritis development

OBJECTIVE

There is a need to better define symptom characteristics associated with arthritis development in individuals at risk of rheumatoid arthritis (RA). We investigated whether reported symptoms in at-risk individuals could predict arthritis development and whether predictive symptoms differed between seropositive and seronegative at-risk individuals.

METHOD

At-risk individuals from four cohorts (Netherlands, UK, Sweden, and Switzerland) completed the Symptoms in Persons At Risk of Rheumatoid Arthritis (SPARRA) questionnaire. Participants had either (i) anti-citrullinated protein antibodies and/or rheumatoid factor, or (ii) relevant symptoms with or without RA antibodies. Follow up was ≥ 24 months or until clinical arthritis development. Stepwise forward selection created SPARRA prediction models for the combined group and for a seropositive subgroup.

RESULTS

Of 214 participants, the mean age was 50 years, 67% were female, and 27% (n = 58) developed clinical arthritis after a median time of 7 months. Four symptoms predicted arthritis development: self-reported joint swelling, joint pain moving from side to side (combined group only), feeling pins and needles in the joints, and often feeling fatigued (predicting non-arthritis).

CONCLUSION

Specific symptoms can provide useful information to estimate a person's RA risk. Differences in predictive symptoms between seropositive and seronegative at-risk individuals need to be further investigated. Future research is needed to determine whether changes in symptoms over time improve prediction and to determine the value of SPARRA in optimizing the selection of individuals who need to consult a rheumatologist.

Baseline serum levels of IgA anti-cyclic citrullinated protein antibodies in early rheumatoid arthritis predict radiographic progression after 11 years of treatment: a secondary analysis of the CIMESTRA study

OBJECTIVE

Smoking and periodontitis are risk factors for developing rheumatoid arthritis (RA), suggesting a break of tolerance on mucosal surfaces. Immunoglobulin A (IgA) antibodies are part of the mucosal immune system. The dominant autoantibodies in RA are anti-cyclic citrullinated protein antibodies (ACPAs), and IgG and IgA subclasses exist simultaneously. This study aimed to investigate the association of ACPA IgA subtypes with disease activity and long-term radiographic outcomes in RA, compared with ACPA IgG.

METHOD

Total ACPA IgG, IgA, IgA1, and IgA2 were quantified in serum from patients with early RA (n = 97). Patient characteristics, IgM rheumatoid factor (IgM-RF) status, clinical and biochemical disease activity scores, and radiographic status evaluated by total Sharp score (TSS), were assessed at baseline and after 2 and 11 years of treatment.

RESULTS

All patients with ACPA IgA also had ACPA IgG. ACPA IgA positivity was associated with IgM-RF and male gender. Both ACPA IgA and IgG levels at baseline were weakly associated with disease activity markers. Baseline ACPA IgA and IgG did not show a linear correlation with radiographic status after 10 years, but could predict radiographic progression (ΔTSS ≥ 5 from 0 to 11 years), with positive likelihood ratios of 3.7 and 4.0, respectively.

CONCLUSION

ACPA IgA and IgG were weakly associated with disease activity in early RA. RA patients with a ΔTSS ≥ 5 after 11 years of treatment had higher ACPA IgG and ACPA IgA levels at baseline; however, none of the ACPA subtypes was superior in predicting long-term radiographic progression.

Biological Agent Switching in Patients With Juvenile Idiopathic Arthritis: A Tertiary Center Experience

OBJECTIVE

The purpose of this study is to investigate the causes and outcomes of switching biological agents in juvenile idiopathic arthritis (JIA) patients using biological agents and compare the characteristics of patients whose biological agents are switched and those whose are not.

METHODS

This medical records review study was conducted with 128 patients who were diagnosed with JIA at our clinic between January 2009 and January 2022 and were receiving biologic agents. Factors affecting the biologic agent switching were investigated.

RESULTS

The JIA subtype with the most frequent switching in biological agents was systemic JIA (n = 13, 40.6%). Systemic JIA was followed by rheumatoid factor-negative polyarticular JIA and persistent oligoarticular JIA with 5 patients (15.6%), extended oligoarticular JIA and enthesitis-related JIA with 3 patients (9.3%), rheumatoid factor-positive polyarticular JIA with 2 patients (6.2%), and undifferentiated JIA with 1 patient (3.1%). Among the patients, 32 (25%) patients had their biological agent switched once, and 5 (3.9%) had theirs switched twice. The most frequently used biological agent was etanercept (n = 76, 59.3%), whereas the most frequently observed cases of biological agent switching were from an anti-TNF agent to another anti-TNF agent (40.6%). The reason for switching was unresponsiveness to the agent in 22 patients (68.8%), adverse effects in 6 patients (18.7%), drug intolerance in 1 patient (3.1%), and other reasons in 3 patients (9.3%).

CONCLUSIONS

The most frequently used biological agent was etanercept; the most frequent cases of biological agents switching were from an anti-TNF agent to another anti-TNF agent.

Lack of comparability of immunoassays for rheumatoid factor isotypes

OBJECTIVES

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterised by the presence of autoantibodies that are used for classification of the disease. Though routine diagnostics is commonly restricted to measuring rheumatoid factor (RF) and anti-citrullinated protein antibodies, detection of RF IgM, IgG and IgA isotypes, may increase the power of RA serodiagnosis by reducing the number of seronegative patients as well as provide prognostic information. The agglutination-based RF assays, such as nephelometry or turbidimetry, are unable to differentiate isotypes. We compared three different immunoassays used in current laboratory practice to detect RF isotypes.

METHODS

We tested 117 consecutive serum samples that were positive for total RF at nephelometry, from 55 RA and 62 non-RA subjects. IgA, IgG, and IgM isotypes of RF were tested by immunoenzymatic (ELISA, Technogenetics), fluoroenzymatic (FEIA, ThermoFisher) and chemiluminescence (CLIA, YHLO Biotech Co.) immunoassays.

RESULTS

Diagnostic performance differed considerably between the assays, especially with regard to RF IgG isotype. Agreement among methods by Cohen's kappa ranged from 0.05 (RF IgG CLIA vs. FEIA) to 0.846 (RF IgM CLIA vs. FEIA).

CONCLUSIONS

The poor agreement observed in this study indicates substantial lack of comparability among assays for RF isotypes. Harmonization of these tests requires further efforts before their measurement can be used in clinical practice.

Clinical characteristics of rheumatoid arthritis patients complicated with pulmonary nontuberculous mycobacterial disease: A cross-sectional case series study

OBJECTIVES

Pulmonary nontuberculous mycobacterial disease (pNTM) is a common pulmonary complication of rheumatoid arthritis (RA), but their association has rarely been researched. We aimed to reveal the clinical characteristics of RA with pNTM.

METHODS

Among all the RA patients who visited Tenri hospital from April 2017 to March 2018, we enrolled those fulfilling the 2007 ATS/IDSA diagnostic criteria of pNTM, and sex- and age- matched control group at a ratio of 1:5. Demographic characteristics were compared between the two groups.

RESULTS

Among 865 RA patients, 35 (4.0%) patients were complicated with pNTM. RA patients with pNTM had significantly lower BMI and higher rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity. Bronchiectasis was the most frequent lesion, followed by clusters of small nodules, patchy consolidation and cavity. Multivariable logistic regression analysis revealed bronchiectasis as a strong independent associated factor of pNTM. Treatment for pNTM was needed in 14 of the 35 (40%) RA patients with pNTM and sputum negative conversion was accomplished in 11 of the 14 cases (78.6%).

CONCLUSIONS

RA patients with lower BMI, RF/ACPA positivity, and bronchiectasis were associated with pNTM. Treatment for pNTM may attain sputum negative conversion and radiological improvement in patients with RA.

Temporomandibular joint involvement in elderly onset and young onset rheumatoid arthritis patients

OBJECTIVE

There are studies showing clinical and laboratory differences between elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis. Temporomandibular joint involvement in rheumatoid arthritis is not rare. In this study, we aimed to examine the temporomandibular joint involvement and magnetic resonance imaging findings in elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis patients.

METHODS

A total of 87 rheumatoid arthritis patients were investigated retrospectively. The onset ≥60 years was considered elderly-onset rheumatoid arthritis. Erosion, flattening, and resorption of the condyle, narrowing of the joint space, joint effusion, synovial hypertrophy, and synovitis were interpreted as temporomandibular joint involvement with magnetic resonance imaging. Patients' age, gender, rheumatoid factor, and anti-cyclic citrullinated peptide positivity, extra-articular findings, medical treatment, and disease activity score were noted.

RESULTS

A total of 15 (17.2%) patients had elderly-onset rheumatoid arthritis. Temporomandibular joint involvement was detected in 67 (77%) patients; 9 (60%) of them were in the elderly-onset rheumatoid arthritis group (n=15) and 58 (80.6%) of them were in the young-onset rheumatoid arthritis group (n=72). Patients with temporomandibular joint involvement were significantly higher than those without temporomandibular joint involvement in both the elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis groups (p<0.001). No significant difference was found between elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis for the temporomandibular joint involvement (p=0.100). In the young-onset rheumatoid arthritis group, rheumatoid factor positivity and anti-cyclic citrullinated peptide positivity were more frequent in the patients with temporomandibular joint involvement (p=0.011, p=0.024). A comparison of the elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis patients showed no significant difference in the magnetic resonance imaging findings except for the resorption of the condyle.

CONCLUSION

According to our findings, elderly-onset rheumatoid arthritis is not much different from young-onset rheumatoid arthritis in terms of temporomandibular joint involvement, magnetic resonance imaging findings, and clinical and laboratory features.

[Significance of IgA isotype of anti-v-raf murine sarcoma viral oncogene homologue B1 antibody in rheumatoid arthritis]

OBJECTIVE

To detect serum IgA isotype of anti-v-raf murine sarcoma viral oncogene homologue B1 (BRAF) antibody levels in the rheumatoid arthritis (RA) patients in order to investigate their clinical significance in RA.

METHODS

Serum samples were obtained from 61 RA patients, 21 osteoarthritis (OA) patients, 16 systemic lupus erythematosus (SLE) patients, 16 gout patients, 16 Sjögren's syndrome (SS) patients and 22 healthy controls. IgA isotype of anti-BRAF antibody levels in the sera were examined by enzyme-linked immunosorbent assay (ELISA). The associations between IgA isotype of anti-BRAF antibody levels and the clinical features including age, disease duration and laboratory parameters including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), disease activity score in 28 joints (DAS28), anti-cyclic citrullinated peptide (anti-CCP) antibody, immunoglobulin and BRAF protein levels in the RA patients were evaluated. Data analyses were performed by using SPSS 19.0 program.

RESULTS

The serum IgA isotype of anti-BRAF antibody levels in the RA patients were significantly higher than in the SLE, gout, OA patients and healthy controls, the P value was 0.011, < 0.001, < 0.001 and < 0.001, respectively. The serum IgA isotype of anti-BRAF antibody levels in the SS patients were also significantly higher than in the SLE, gout, OA patients and healthy controls, the P value was 0.029, 0.004, 0.001 and < 0.001, respectively. However, there was no difference between the RA and SS patients (P=0.762). IgA isotype of anti-BRAF antibody was measurable in the RA patients without RF, anti-CCP antibody or anti-keratin antibody (AKA) antibodies. The levels of IgA isotype of anti-BRAF antibody in the RA patients did not show any correlation with clinical features such as age and disease duration or laboratory parameters including ESR, CRP, RF, DAS28, anti-CCP antibody, immunoglobulin and BRAF protein levels. Compared with the clinical features and laboratory indexes of normal and elevated levels of IgA isotype of anti-BRAF antibody groups in the RA patients, there was no significant differences between the two groups in age, disease duration, ESR, CRP, RF, DAS28, anti-CCP antibody, immunoglobulin or BRAF protein levels.

CONCLUSION

The elevated level of IgA isotype of anti-BRAF antibody in the RA patients showed that IgA isotype of anti-BRAF antibody might play a role in the pathogenesis of RA. Furthermore, detection of IgA isotype of anti-BRAF antibody in the serum negative RA patients showed that it might be helpful for the diagnosis of the serum negative RA patients.

Expenditure of biological drugs for rheumatoid arthritis treatment in the Brazilian public health system

OBJECTIVE

This work aims to analyze the quantity and expenses related to biological drugs used for the treatment of rheumatoid arthritis (RA) in outpatient public care within the Brazilian Unified Health System (SUS).

METHODS

It is a cross-sectional descriptive study based on secondary data from a historical series, referring to the purchase, volume, and the number of patients treated with different biological drugs (infliximabe, etanercept, adalimumab, rituximab, abatacept, tocilizumab, golimumab, and certolizumab pegol) for RA treatment in outpatient care from 2012 to 2017. The data were extracted from the SUS Outpatient Information System database-SIA/SUS and included ten drugs used for RA treatment. The study assessed the quantity and expenditure of these drugs, the number of RA patients treated, and the expenditure by RA subtypes. The National Broad Consumer Price Index was used to adjust the expenditures for December 2017.

RESULTS

The Ministry of Health allocated approximately $500 million to provide about 2 million units of biological drugs for RA patients from 2012 to 2017. The supply of adalimumab 40 mg and etanercept 50 mg accounted for 68.3% of the total expenditure. The subtypes "other rheumatoid arthritis with rheumatoid factor" (ICD-10 M05.8), "rheumatoid arthritis without rheumatoid factor" (ICD-10 M06.0), and "Felty's syndrome" (M05. 0) represented 84.5% of the total expenditures. The proportion of patients treated with biological drugs increased by 33.0%. There was a significant 83.0% increase in the number of patients using biological drugs compared to the overall number of RA patients treated during the study period.

CONCLUSIONS

The results obtained allow us to draw a more recent profile of expenditure on RA treatment and indicate trends in the use of biological drugs for this condition, generating data that can support management decisions in public health policies.

Rheumatic manifestations of hepatitis C virus infection are associated with autoantibodies but not viremia

BACKGROUND

To investigate the associations between extrahepatic manifestations, autoantibodies, and viremia in patients with hepatitis C virus (HCV) infection.

METHODS

This cross-sectional study recruited patients with HCV infection from the outpatient department of a tertiary medical center in Northern Taiwan between January 2017 and August 2019. Autoantibody profiles and the clinical parameters of HCV infection were evaluated using laboratory tests, and a questionnaire was used to record extrahepatic manifestations. HCV infection status, including inactive HCV infection, active hepatitis, and cirrhosis, was defined according to abdominal ultrasonography findings and alanine transaminase levels.

RESULTS

A total of 77 patients with HCV were recruited, with 19.5% and 16.9% of patients, respectively, presenting with arthritis and dry eyes. Autoantibody screening revealed rheumatoid factor (RF), antinuclear antibody (ANA), anti-Ro antibody, and anti-La antibody positivity in 20.8%, 23.4%, 13.0%, and 2.6% of the patients, respectively. The presence of RF was associated with arthritis, whereas the presence of ANA was associated with dry eyes but not dry mouth. Active hepatitis and HCV-related cirrhosis were associated with viremia, but not autoantibody profiles.

CONCLUSION

In this single-center study, the prevalence of extrahepatic manifestations and autoantibodies did not differ in patients stratified by the HCV infection status. Rheumatic manifestations were associated with the presence of autoantibodies but not with viremia.

A study of the roles of some immunological biomarkers in the diagnosis of rheumatoid arthritis

Autoimmune rheumatoid arthritis (RA) is a systemic condition closely correlated with a variety of autoantibodies (Abs) that could be considered diagnostic and prognostic markers. The current research was designed to detect the diagnostic values for a number (n) of these auto-Abs in RA detection and to evaluate the accuracy of a combined diagnostic scheme. This prospective study was conducted between September 2021 and August 2022 and included 110 subjects with RA, 70 individuals with other autoimmune disorders as positive controls (PC), and 50 unrelated, apparently healthy individuals as healthy controls (HC). The eligibility criteria for all study groups were followed stringently. An enzyme-linked immunosorbent assay (ELISA) was employed to measure rheumatoid factors (RF), cyclic citrullinated peptide antibodies (CCP-Abs), mutated citrullinated vimentin antibodies (MCV-Abs), anti-perinuclear factor antibodies (APF-Abs), and anti-keratin antibodies (AKA). We calculated the specificity, sensitivity, and predictive values of all auto-Abs. Significantly higher levels of anti-CCP-Abs, anti-MCV-Abs, APF-Abs, and AKAs were reported in the RA patients compared to the HC and PC subjects. RF levels, however, were only statistically elevated when compared to the HC individuals. Anti-APF-Abs had a higher sensitivity rate (70.9%), and anti-CCP-Abs had a higher specificity rate (94.16%) compared to other auto-Abs, whereas the combined detection scheme revealed a higher sensitivity (81.81%) and excellent specificity (90.83%) compared to the two former auto-Abs. Anti-perinuclear factor-Ab was a highly sensitive test, and CCP-Ab was a surpassingly specific assay for identifying RA. Furthermore, the combined detection scheme is an essential serological approach for RA diagnosis and crucial in differentiating this disease from other autoimmune diseases, thus promoting early diagnosis and treatment.

Falsely decreased vancomycin caused by rheumatoid factor: A case report

BACKGROUND

Vancomycin is associated with potential nephrotoxicity and trough concentrations need to be monitored in certain patients. Falsely decreased vancomycin measurement may result in overtreatment and need to be identified promptly by clinicians and pharmacists to avoid toxicities.

METHODS AND RESULTS

We report a case of rheumatoid factor-mediated falsely low vancomycin measurement with Abbott particle-enhanced turbidimetric inhibition immunoassay (PETINIA) method. Reanalyzing the sample using an alternative method, removing the interferences using heterophile blocking reagent as well as rheumatoid factor clean-up solution all helped to solve the false results. Results from alternative method and interference studies showed vancomycin concentrations reached toxic concentrations in the patient and administration of the drug was immediately terminated. The patient experienced a transient increase in serum creatinine.

CONCLUSIONS

Even though most modern immunoassays use blocking agents to neutralize interfering antibodies such as rheumatoid factor, it is important for health care professionals to understand that occasional interference still occurs due to the heterogeneous nature of rheumatoid factor.

The MIDORA trial: a phase II, randomised, double-blind, placebo-controlled, mechanistic insight and dosage optimisation study of the efficacy and safety of dazodalibep in patients with rheumatoid arthritis

OBJECTIVES

To evaluate the safety, efficacy and response duration of four different dosing regimens of dazodalibep (DAZ), a non-antibody biological antagonist of CD40L, in patients with rheumatoid arthritis (RA).

METHODS

This double-blind study included adult patients with moderate-to-severe active RA with a positive test for serum rheumatoid factor and/or anticitrullinated protein antibodies, an inadequate response to methotrexate, other conventional disease-modifying antirheumatic drugs or tumour necrosis factor-α inhibitors, and no prior treatment with B-cell depleting agents. Eligible participants were randomised equally to five groups receiving intravenous infusions of DAZ or placebo. The primary endpoint was the change from baseline in the Disease Activity Score-28 with C reactive protein (DAS28-CRP) at day 113. Participants were followed through day 309.

RESULTS

The study randomised 78 eligible participants. The change from baseline in DAS28-CRP (least squares means±SE) at day 113 was significantly greater for all DAZ groups (-1.83±0.28 to -1.90±0.27; p<0.05) relative to PBO (-1.06±0.26); significant reductions in DAS28-CRP were also observed for all DAZ groups at day 309. The distribution of adverse events was generally balanced among DAZ and PBO groups (74% and 63%, respectively). There were four serious adverse events deemed by investigators to be unrelated to study medication.

CONCLUSIONS

DAZ treatment for all dosage regimens significantly reduced DAS28-CRP at day 113 relative to PBO. The safety data suggest an acceptable safety and tolerability profile. Treatment effects at day 113 and the prolonged duration of responses after DAZ cessation support the use of longer dosing intervals.

TRIAL REGISTRATION NUMBER

NCT04163991.

Rheumatoid factor isotypes in rheumatoid arthritis diagnosis and prognosis: a systematic review and meta-analysis

OBJECTIVE

The first biomarker associated with the rheumatoid arthritis is rheumatoid factor (RF) and since the earliest reports a role has been proposed in the diagnosis and in the prediction of clinical features and outcome. The study of RF isotypes has further attempted to improve diagnostic accuracy and identify specific subgroups of patients. The main objective of this study is to provide an analysis of the literature on the role of RF isotypes in the diagnosis and prognosis of rheumatoid arthritis (RA).

METHODS

We performed a systematic literature review and meta-analysis on the role of RF isotypes in RA (only in English, from PubMed, search terms: "rheumatoid factor isotypes", "diagnosis", "prognosis" and "rheumatoid arthritis", last search 31 July 2022, two independent assessment of quality and biases, results included in tables and in the meta-analysis).

RESULTS

Thirty-six articles were examined (7517 patients). Testing all RF isotypes with latex test or nephelometry allows for the highest sensitivity (68.6%, 95% CI 66.2% to 71.0%); nonetheless, the determination of IgA isotype provides the highest specificity (91.4%, 95% CI 90.8% to 92.0%) and the highest positive likelihood ratio (7.7, 95% CI 5.7 to 10.4). When testing IgM isotype the highest diagnostic OR (21.7, 95% CI 16.1 to 29.3) is reached. When analysing anti-citrullinated protein antibodies, RF isotype determination increases diagnostic accuracy. On the other hand, these do not provide relevant prognostic information, as results are conflicting.

CONCLUSIONS

Testing RF allows the highest sensitivity, while IgA isotype the highest specificity and positive likelihood ratio for RA diagnosis. On the other hand, determination of RF isotypes dose not allow prognostic information, as data are limited and heterogeneous.

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.

[Rheumatoid factor: study history and concept evolution]

Rheumatoid factor became the first laboratory marker of rheumatoid arthritis and one of the first serological markers used to recognize the major autoimmune diseases. Details of the discovery with special regard to contribution of E. Waaler and H. Rose are presented in this historical review. Same assays used to exam the rheumatoid factor, its frequency and modern view on diagnostic significance in different diseases are described in this article.

Factors associated with interstitial lung disease in patients with rheumatoid arthritis: A systematic review and meta-analysis

OBJECTIVES

Interstitial lung disease (ILD) is frequent in patients with rheumatoid arthritis (RA) and is a potentially life-threatening complication with significant morbidity and mortality. This meta-analysis aims to systematically determine the factors associated with the development of rheumatoid arthritis-related interstitial lung disease (RA-ILD).

MATERIALS AND METHODS

All primary studies which reported the factors associated with of RA-ILD were eligible for the review except case reports. The Cochrane Library, PubMed, Embase, Web of Science, Chinese Biological Medicine Database (CBM), China National Knowledge Infrastructure (CNKI), and WANFANG electronic databases were searched through to December 30, 2022, for studies investigating the factors associated with RA-ILD. The methodological quality assessment of the eligible studies was performed using the Newcastle-Ottawa Scale (NOS). 2 reviewers extracted relevant data independently. Then, weighed mean differences (WMDs) or pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were obtained for the relationships between the factors and RA-ILD. The statistical meta-analysis, subgroup and sensitivity analyses were performed using the Review Manager 5.3, and publication bias with Egger's test were performed using the Stata12.0 software.

RESULTS

A total of 22 articles were screened for a meta-analysis which involved 1887 RA-ILD patients and 8066 RA without ILD patients. Some identified factors that were associated with an increased risk of RA-ILD included male sex (OR = 1.92, 95% CI: 1.54-2.39; P < 0.00001), older age (WMD = 5.77 years, 95% CI: 3.50-8.04; P < 0.00001), longer duration of RA (WMD = 0.80 years, 95% CI 0.12-1.47; P = 0.02), older age at onset of RA (WMD = 6.41 years, 95% CI: 3.17-9.64; P = 0.0001), smoking (OR = 1.69, 95% CI: 1.30-2.18; P < 0.0001). Five factors of laboratory items associated with the development of RA-ILD were evaluated in the meta-analysis. Compared with RA without ILD patients, positive rheumatoid factor (RF) (OR = 1.72, 95% CI: 1.47-2.01; P < 0.00001) and positive anti-citrullinated protein antibodies (ACPA) (OR = 1.58, 95% CI: 1.31-1.90; P < 0.00001) increased the risk of RA-ILD. Meanwhile, RF titer (WMD = 183.62 (IU/mL), 95% CI: 66.94-300.30; P = 0.002) and ACPA titer (WMD = 194.18 (IU/mL), 95% CI: 115.89-272.47; P < 0.00001) were significantly associated with increased risk of RA-ILD. Elevated erythrocyte sedimentation rate (ESR) (WMD = 7.41 (mm/h), 95% CI: 2.21-12.61; P = 0.005) and C-reactive protein (CRP) (WMD = 4.98 (mg/L), 95% CI: 0.76-9.20; P = 0.02) were also significantly associated with the development of the RA-ILD, whereas antinuclear antibody (ANA) positive status was not significantly associated with increased risk of RA-ILD (OR = 1.27, 95% CI: 1.00-1.60; P = 0.05).

CONCLUSIONS

This meta-analysis showed that male gender, older age, longer duration of RA, older age at onset of RA, smoking, positive RF, positive ACPA, elevated RF titer, elevated ACPA titer, higher ESR and higher CRP were associated with RA-ILD.

Impact of treatment with direct-acting antivirals on inflammatory markers and autoantibodies in HIV/HCV co-infected individuals

HCV infection could have extrahepatic manifestations due to an aberrant immune response. HCV/HIV co-infection increases such persistent immune activation. Aim of the present study is to describe the evolution of inflammatory markers used in clinical practice, mixed cryoglobulinemia (MC) and autoantibody reactivity in co-infected individuals who achieved sustained virological response (SVR) after DAA treatment. This prospective, observational study included all HIV/HCV co-infected subjects who started any DAA regimen from 2015 to 2020. Samples for laboratory measurements (ferritin, C reactive protein, C3 and C4 fractions, rheumatoid factor, MC, anti-thyroglobulin Ab, anti-thyroid peroxidase Ab, ANCA, ASMA, anti-LKM, anti-DNA, AMA, ANA, T CD4+ and CD8+ cell count, and CD4/CD8 ratio) were collected at baseline, after 4 weeks, at end of treatment, and at SVR12. The analysis included 129 individuals: 51.9% with a F0-F3 fibrosis and 48.1% with liver cirrhosis. Cryocrit, C3 fraction, and rheumatoid factor significantly improved at week 4; ferritin, anti-thyroglobulin Ab, and C4 fraction at EOT; total leukocytes count at SVR12. MC positivity decreased from 72.8% to 35.8% (p < .001). T CD4+ cell slightly increased at SVR12, but with an increase also in CD8+ resulting in stable CD4/CD8 ratio. Autoantibody reactivity did not change significantly. ANA rods and rings positivity increased from 14.8% to 28.6% (p = .099): they were observed in three subjects without exposure to RBV. DAA therapy may lead to improvement in inflammatory markers and MC clearance but without significant changes in autoantibodies reactivity and CD4/CD8 ratio over a follow up of 12 weeks.

Effect of curcumin on rheumatoid arthritis: a systematic review and meta-analysis

Objective

The aim of this study is to evaluate the effectiveness and safety of curcumin in rheumatoid arthritis patients.

Methods

A computerized search from PubMed, Embase, Cochrane Library, and Web of Science databases was performed until 3 March 2023. Literature screening, basic data extraction and risk of bias evaluation were independently performed by two researchers each. The quality evaluation of the literature was performed according to the Cochrane Handbook for Risk of Bias Assessment tool for treatment evaluation.

Results

The current study includes six publications covering 539 rheumatoid arthritis patients. The activity of rheumatoid arthritis was assessed using erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), protein, disease activity score (DAS), rheumatoid factor (RF), Visual Analogue Scale (VAS) pain, tender joint count (TJC) and swollen joint count (SJC). ESR (MD = -29.47, 95% CI [-54.05, -4.88], Z=2.35, P = 0.02), DAS28 (MD = -1.20, 95% CI [-1.85, -0.55], Z=3.62, P = 0.0003), SJC (MD = -5.33, 95% CI [-9.90, -0.76], Z = 2.29, P = 0.02) and TJC (MD = -6.33, 95% CI [-10.86, -1.81], Z = 2.74, P = 0.006) showed significantly change in experimental patients compared with controls.

Conclusion

Curcumin is beneficial for rheumatoid arthritis treatment. Inflammation levels and clinical symptoms in patients with rheumatoid arthritis can be improved by curcumin supplementation. Large sample randomized controlled trials on the effects of curcumin on patients with rheumatoid arthritis are needed in the future.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier (CRD42022361992).

Validation of serostatus of rheumatoid arthritis using ICD-10 codes in administrative claims data

PURPOSE

To determine the accuracy of International Classification of Diseases- Tenth Revision (ICD-10) diagnosis codes for rheumatoid arthritis (RA) serostatus using a U.S. claims database (Optum Clinformatics Data Mart, Optum) and to compare the results to a previous validation study performed in IBM Marketscan Research Database (sensitivity 73%, positive predictive value, PPV, 84%).

METHODS

In Optum (01/01/2016-03/31/2020) linked with laboratory results, we selected RA patients based on ≥2 ICD-10 diagnosis codes for RA (M05 or M06) and at least one dispensing of RA treatments. We included individuals with at least one laboratory result for rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) performed 365 days prior to and including the cohort entry date. An individual was "seropositive" if at least one of the 2 diagnosis codes used to define RA status was M05. "Seronegative" patients were required to have only M06. Secondary analyses were performed using subsets of M05 and M06 diagnosis codes. We calculated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and kappa of M05 and M06 against the prespecified reference standard laboratory data.

RESULTS

We identified 14 490 adult RA patients who had at least 1 RF or anti-CCP result. The number of patients identified for each reference standard definition ranged from 3315 (reference standard definition: high + anti-CCP) to 13 636 (any + RF). PPV for seropositive RA, M05, was 77.1%. The PPV of M06 for seronegative RA was 61.6%. When we applied more restricted definitions of M05 and M06, the PPV for seropositive RA increased to 79.2%. The PPV for seronegative RA also notably increased to 89.5%.

CONCLUSION

ICD-10 codes (M05 and M06) can help identify RA serostatus in claims data, but their limitations should be acknowledged. The PPVs for seropositive and seronegative RA found in the Optum database were lower than those found in MarketScan, perhaps related to database variability or differing patient characteristics and clinical practice. When more restricted definitions of M05 and M06 were used, the PPVs for seropositive and seronegative RA improved to 79.2% and 89.5%, respectively.

Serum antibodies to periodontal pathogens prior to rheumatoid arthritis diagnosis: A case-control study

OBJECTIVES

1) To quantify the association between anti-Porphyromonas gingivalis serum antibody concentrations and the risk of developing rheumatoid arthritis (RA), and 2) to quantify the associations among RA cases between anti-P. gingivalis serum antibody concentrations and RA-specific autoantibodies. Additional anti-bacterial antibodies evaluated included anti-Fusobacterium nucleatum and anti-Prevotella intermedia.

METHODS

Serum samples were acquired pre- and post- RA diagnosis from the U.S. Department of Defense Serum Repository (n = 214 cases, 210 matched controls). Using separate mixed-models, the timing of elevations of anti-P. gingivalis, anti-P. intermedia, and anti-F. nucleatum antibody concentrations relative to RA diagnosis were compared in RA cases versus controls. Associations were determined between serum anti-CCP2, ACPA fine specificities (vimentin, histone, and alpha-enolase), and IgA, IgG, and IgM RF in pre-RA diagnosis samples and anti-bacterial antibodies using mixed-effects linear regression models.

RESULTS

No compelling evidence of case-control divergence in serum anti-P. gingivalis, anti-F. nucleatum, and anti-P. intermedia was observed. Among RA cases, including all pre-diagnosis serum samples, anti-P. intermedia was significantly positively associated with anti-CCP2, ACPA fine specificities targeting vimentin, histone, alpha-enolase, and IgA RF (p<0.001), IgG RF (p = 0.049), and IgM RF (p = 0.004), while anti-P. gingivalis and anti-F. nucleatum were not.

CONCLUSIONS

No longitudinal elevations of anti-bacterial serum antibody concentrations were observed in RA patients prior to RA diagnosis compared to controls. However, anti-P. intermedia displayed significant associations with RA autoantibody concentrations prior to RA diagnosis, suggesting a potential role of this organism in progression towards clinically-detectable RA.