Agreement between local and central anti-synthetase antibodies detection: results from the Classification Criteria of Anti-Synthetase Syndrome project biobank.

OBJECTIVES: The CLASS (Classification Criteria of Anti-Synthetase Syndrome) project is a large international multicentre study that aims to create the first data-driven anti-synthetase syndrome (ASSD) classification criteria. Identifying anti-aminoacyl tRNA synthetase antibodies (anti-ARS) is crucial for diagnosis, and several commercial immunoassays are now available for this purpose. However, using these assays risks yielding false-positive or false-negative results, potentially leading to misdiagnosis. The established reference standard for detecting anti-ARS is immunoprecipitation (IP), typically employed in research rather than routine autoantibody testing. We gathered samples from participating centers and results from local anti-ARS testing. As an "ad-interim" study within the CLASS project, we aimed to assess how local immunoassays perform in real-world settings compared to our central definition of anti-ARS positivity. METHODS: We collected 787 serum samples from participating centres for the CLASS project and their local anti-ARS test results. These samples underwent initial central testing using RNA-IP. Following this, the specificity of ARS was reconfirmed centrally through ELISA, line-blot assay (LIA), and, in cases of conflicting results, protein-IP. The sensitivity, specificity, positive likelihood ratio and positive and negative predictive values were evaluated. We also calculated the inter-rater agreement between central and local results using a weighted κ co-efficient. RESULTS: Our analysis demonstrates that local, real-world detection of anti-Jo1 is reliable with high sensitivity and specificity with a very good level of agreement with our central definition of anti-Jo1 antibody positivity. However, the agreement between local immunoassay and central determination of anti-non-Jo1 antibodies varied, especially among results obtained using local LIA, ELISA and "other" methods. CONCLUSIONS: Our study evaluates the performance of real-world identification of anti-synthetase antibodies in a large cohort of multi-national patients with ASSD and controls. Our analysis reinforces the reliability of real-world anti-Jo1 detection methods. In contrast, challenges persist for anti-non-Jo1 identification, particularly anti-PL7 and rarer antibodies such as anti-OJ/KS. Clinicians should exercise caution when interpreting anti-synthetase antibodies, especially when commercial immunoassays test positive for non-anti-Jo1 antibodies.

Synovial and serum B-cell signature of autoantibody-negative rheumatoid arthritis versus autoantibody-positive rheumatoid arthritis and psoriatic arthritis.

OBJECTIVES: Autoantibody-negative rheumatoid arthritis (RA) differs from autoantibody-positive RA in several clinical aspects, possibly underpinned by pathogenetic differences. At present, the role of adaptive immune responses in autoantibody-negative RA remains unclear. Here, we investigated the synovial and serum immunophenotype indicative of B-lymphocyte involvement across the spectrum of autoantibody-positive and -negative chronic arthritides. METHODS: Ultrasound-guided synovial biopsies were retrieved from 131 patients: 43 autoantibody-positive RA, 35 autoantibody-negative RA, 25 polyarticular psoriatic arthritis (PsA), 28 oligoarticular PsA. Samples were analysed for the degree of histological inflammation, B-lymphocyte infiltration and the distribution of different pathotypes (lympho-myeloid, myeloid, pauci-immune). Serum levels of the B-cell chemoattractant CXCL13 were compared among groups. RESULTS: Synovitis scores and CD68+ sublining macrophage infiltration were comparable irrespective of clinical diagnosis and disease subtype. In contrast, the degree of B-lymphocyte infiltration and the frequency of lympho-myeloid synovitis in autoantibody-negative RA were lower than those of autoantibody-positive RA (mean [SD] 1.8 [1] vs 2.4 [0.6], p = 0.03 and 38.2% vs 62.9%, p = 0.07, respectively), and similar to polyarticular PsA. Oligoarticular PsA had the lowest B-cell scores. Serum CXCL13 was associated with lympho-myeloid synovitis and followed a similar gradient, with the highest levels in autoantibody-positive RA, intermediate and comparable levels in autoantibody-negative RA and polyarticular PsA, and low levels in oligoarticular PsA. CONCLUSIONS: The synovial and serum immunophenotype indicative of B-lymphocyte involvement in autoantibody-negative RA differs from autoantibody-positive RA and more closely resembles that observed in polyarticular PsA. The pathobiological stratification of chronic inflammatory arthritides beyond clinical diagnosis may fuel personalised treatment strategies.

Immunosuppressive treatments selectively affect the humoral and cellular response to SARS-CoV-2 in vaccinated patients with vasculitis.

OBJECTIVES: To analyse humoral and cellular immune response to mRNA COVID-19 vaccines in patients with GCA. METHODS: Consecutive patients with a diagnosis of GCA receiving two doses of BNT162b2 vaccine were assessed at baseline and 3 weeks from the second vaccine dose. Healthy subjects (n = 51) were included as controls (HC). Humoral response was assessed with Spike-specific IgG antibody response (S-IgG) and neutralizing antibodies (NtAb). Specific T cell response was assessed by enzyme linked immunosorbent spot (ELISpot). RESULTS: Of 56 included patients with GCA, 44 were eligible after exclusion of previous evidence of COVID-19 and incomplete follow-up. A significant proportion of patients with GCA (91%) demonstrated antibody (S-IgG) response, but this was significantly lower than HCs (100%); P < 0.0001. Neutralizing activity was not detected in 16% of patients with GCA. Antibody titres (S-IgG and NtAb) were significantly lower compared with HCs. Humoral response (S-IgG and NtAb) was significantly hampered by treatment with MTX. Cellular response was lacking in 30% of patients with GCA (vs 0% in HCs; P < 0.0001). Cellular response was significantly influenced by the levels of baseline peripheral T-lymphocytes and by glucocorticoid treatment. Treatment with tocilizumab did not affect any level of the immune response elicited by vaccination. CONCLUSIONS: Although patients with GCA apparently achieve a robust antibody seroconversion, there is a significant impairment of the neutralizing activity. MTX significantly reduced all levels of the humoral response. Up to one-third of patients do not develop a cellular immune protection in response to COVID-19 vaccination.

Seronegative rheumatoid arthritis: one year in review 2023.

In the past 20 years, earlier diagnosis and more intensive management have considerably improved the prognosis of rheumatoid arthritis (RA), with milder disease course achieved in particular in seropositive patients. In contrast, seronegative RA has remained largely neglected, and continues to be surrounded by uncertainties regarding its correct diagnosis, clinical phenotype, optimal treatment strategies and relevant outcomes.The purpose of this review is to summarise new insights about the pathogenic, clinical and prognostic peculiarities of seronegative RA that emerged during 2022, and that make this disease subset at least partially different from its seropositive counterpart.

Cytomegalovirus colitis unmasking human immunodeficiency virus infection as a cause of IgA vasculitis.

BACKGROUND: Human immunodeficiency virus (HIV) has a protean clinical picture, in rare instances manifesting as systemic autoimmune disorders such as vasculitides. HIV-induced autoimmune diseases often do not respond well to systemic immunosuppressive therapy. Opportunistic infections may occur in patients with either acquired immunodeficiency syndrome (AIDS) or heavy immunosuppressive treatment, and can further complicate the clinical presentation. CASE PRESENTATION: A patient presenting with immunoglobulin A (IgA) vasculitis (IgAV) with treatment-refractory purpuric skin rash and suspect intestinal vasculitis was discovered to have AIDS. HIV was the trigger of IgAV, and cytomegalovirus (CMV) colitis mimicked intestinal vasculitis. Antiretroviral treatment improved both CMV colitis and the control of the autoimmune disease. CONCLUSIONS: An autoimmune disease relapsing despite adequate immunosuppressive treatment and/or the presence of recurrent severe opportunistic infections may be clues to an underlying HIV infection.

Cytokine profile, ferritin and multi-visceral involvement characterize macrophage activation syndrome during adult-onset Still's disease.

OBJECTIVES: To multidimensionally characterize macrophage activation syndrome (MAS) complicating adult-onset Still's disease (AOSD) considering cytokine profile, inflammatory markers and multi-visceral involvement of the disease. To perform a high-dimensional phenotypic analysis of circulating immune cells in AOSD patients with and without MAS. To assess interferon (IFN)-related pathways in AOSD synovial tissues by a bulky RNA sequencing. METHODS: Clinical and biologic data were collected and compared in AOSD patients with and without MAS. Sera biomolecules were analysed by Luminex multiplexing technology. Mass cytometry (CyTOF) was used to characterize circulating immune cells. A bulky RNA sequencing was performed in AOSD synovial tissues. RESULTS: Forty consecutive AOSD patients were assessed, 14 complicated with MAS. Paralleling with increases of systemic score and ferritin, MAS patients showed higher levels of IL-1α, IL-1ß, IL-1Ra, IL-2Ra, IL-6, IL-10, IL-17A, IFN-γ, G-CSF, MCP-1, MIP-1α and SCF. Combining the discriminatory ability of these data in identifying MAS, the best model was composed by systemic score, ferritin, IFN-γ and IL-10. By CyTOF analysis, MAS patients showed an increase of circulating 'classical monocytes' and a reduction of total NK cells. Our assessment showed 3477 IFN-related genes (IRGs) were differently expressed in AOSD synovial tissues. CONCLUSIONS: A multidimensional characterization of AOSD patients suggested that IFN-γ, IL-10, ferritin and systemic score discriminated the occurrence of cytokine storm syndrome associated with MAS. The inflammatory milieu of AOSD and MAS may be related to a signature of circulating immune cells. Finally, our results about IRGs reinforced the role of IFN-γ in these patients.

Anti-Ro52 antibodies positivity in antisynthetase syndrome: a single centre cohort study.

OBJECTIVES: Although antisynthetase antibodies (ARS) are the established markers of the so-called antisynthetase syndrome (ASSD), in these patients the concomitant positivity of anti-Ro52 antibodies, reported in up to the 50% of cases, is not rare. Several studies focused on the effect of different ARS specificities on the evolution of ASSD, the most recent showing no effects. On the contrary, the role of co-occurring anti-Ro52 antibodies in ASSD is still debated. We investigated the potential of anti-Ro52 antibodies in identifying a clinical phenotype of ASSD or influencing prognosis, irrespectively to the underlying ARS specificity. METHODS: Retrospective analysis of clinical, imaging and laboratory characteristics, therapeutic approaches and outcome at baseline and at last follow-up, of 60 ASSD patients progressively enrolled at our Hospital. RESULTS: We identified 34 anti-Ro+ and 26 anti-Ro- ASSD patients. Classic triad prevalence at baseline was similar between the two groups, whereas interstitial lung disease (ILD) (p value=0.01) and myositis (p value=0.03) were significantly more prevalent in anti-Ro52+ and in anti-Ro52- patients at last follow up, respectively. No differences in therapeutic approaches, oxygen need and ILD patterns were observed. Overall mortality was 25% (15 subjects). No differences in mortality, overall and disease related, between anti-Ro52+ and anti-Ro52- patients were observed (p value=0.764), despite the more frequent ILD occurrence in anti-Ro52+ patients. Survival curves were not different at any time point (Log-rank test, p value 0.98). CONCLUSIONS: Anti-Ro52 antibodies affect time course and clinical characteristics of ASSD. Although ILD is significantly more associated to anti-Ro52 antibodies, no difference in mortality was observed compared to anti-Ro52 negative patients.

Blood biomarkers recommended for diagnosing and monitoring IgG4-related disease. Considerations from the ERN ReCONNET and collaborating partners.

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a chronic, clinically heterogenous fibroinflammatory condition, characterised by an accumulation of IgG4 secreting plasma cells in affected tissues and associated with increased serum IgG4 concentrations. Despite a growing recognition of the disease among clinicians from different specialties worldwide, its indolent nature, lack of a single diagnostic test and ability to mimic other malignant, infective and inflammatory conditions, makes the diagnosis challenging. As treatment options evolve, biomarkers correlating with disease activity, predicting prognosis and response to treatment are deemed required. A multidisciplinary panel of experts from the European Reference Network for Rare and Complex Connective tissue diseases (ERN ReCONNET) and affiliated international partners have performed a narrative literature search and reviewed the current evidence of biomarkers in IgG4-RD, including immunoglobulins, cytokines, chemokines and other soluble immune mediators, and cellular components of the immune system. The aim of this paper is to provide useful information for clinicians as to the utility of biomarkers for diagnosing and monitoring IgG4-RD in clinical routine and sets out recommendations for clinical decision making.

Methotrexate and rheumatoid arthritis associated interstitial lung disease.

QUESTION ADDRESSED BY THE STUDY: Methotrexate (MTX) is a key anchor drug for rheumatoid arthritis (RA) management. Fibrotic interstitial lung disease (ILD) is a common complication of RA. Whether MTX exposure increases the risk of ILD in patients with RA is disputed. We aimed to evaluate the association of prior MTX use with development of RA-ILD. METHODS: Through a case-control study design with discovery and international replication samples, we examined the association of MTX exposure with ILD in 410 patients with chronic fibrotic ILD associated with RA (RA-ILD) and 673 patients with RA without ILD. Estimates were pooled over the different samples using meta-analysis techniques. RESULTS: Analysis of the discovery sample revealed an inverse relationship between MTX exposure and RA-ILD (adjusted OR 0.46, 95% CI 0.24-0.90; p=0.022), which was confirmed in the replication samples (pooled adjusted OR 0.39, 95% CI 0.19-0.79; p=0.009). The combined estimate using both the derivation and validation samples revealed an adjusted OR of 0.43 (95% CI 0.26-0.69; p=0.0006). MTX ever-users were less frequent among patients with RA-ILD compared to those without ILD, irrespective of chest high-resolution computed tomography pattern. In patients with RA-ILD, ILD detection was significantly delayed in MTX ever-users compared to never-users (11.4±10.4 years and 4.0±7.4 years, respectively; p<0.001). ANSWER TO THE QUESTION: Our results suggest that MTX use is not associated with an increased risk of RA-ILD in patients with RA, and that ILD was detected later in MTX-treated patients.

Effects of glucocorticoids on B-cell subpopulations in patients with IgG4-related disease.

OBJECTIVES: Glucocorticoids induce prompt clinical improvement in patients with IgG4-related disease (IgG4-RD) but their mechanisms of action in this specific condition are not fully understood. B lymphocytes appear central to IgG4-RD pathogenesis because B-cell depletion with rituximab leads to swift clinical responses. In the present work we aim to assess the effects of glucocorticoids on B-cell subpopulations in patients with IgG4-RD. METHODS: Fifty patients with active untreated IgG4-RD and 20 healthy controls were enrolled in the present study. Flow cytometry analysis for total circulating CD19+ and CD20+ cells, naïve B cells, memory B cells, plasmablasts, and plasma cells was performed at baseline in all patients, and after 6 months of glucocorticoid treatment in 30 patients. Correlation studies with biomarkers of disease activity were also performed. RESULTS: At baseline, patients with IgG4-RD showed reduced CD19+ and CD20+ B cells compared to healthy controls, but increased circulating plasmablasts and plasma cells. Circulating plasmablasts and plasma cells correlated with clinical and serological biomarkers of IgG4-RD activity. Glucocorticoid-induced disease remission was accompanied by a reduction of naïve B cell count, an increase of memory B cells, and by a depletion of circulating plasmablasts and plasma cells. CD19+ and CD20+ B cells, were not affected by glucocorticoids. CONCLUSIONS: The efficacy of glucocorticoids in IgG4-RD is associated with selective effects on different B-cell subpopulations. Further studies are warranted to fully understand possible perturbations of the naïve and memory B-cell compartments in patients with IgG4-RD.

IgG4-related disease.

PURPOSE OF REVIEW: Remarkable insights have been gleaned recently with regard to the pathophysiology of IgG4-related disease (IgG4-RD). These findings have direct implications for the development of targeted strategies for the treatment of this condition. RECENT FINDINGS: Oligoclonal expansions of cells of both the B and T lymphocyte lineages are present in the blood of patients with IgG4-RD. Oligoclonal expansions of plasmablasts are a good biomarker for disease activity. An oligoclonally expanded population of CD4+ cytotoxic T lymphocytes is found not only in the peripheral blood but also at tissue sites of active disease. This cell elaborates cytokines that may drive the fibrosis characteristic of IgG4-RD. T follicular helper cells (Tfhc), particularly the Tfhc2 subset, appear to play a major role in driving the class switch to IgG4 that typifies this disease. The relationship between malignancy and IgG4-RD remains an area of interest. SUMMARY: Advances in understanding the pathophysiology of IgG4-RD have proceeded swiftly, leading to the identification of a number of potential targeted treatment strategies. The completion of classification criteria for IgG4-RD, an effort supported jointly by the American College of Rheumatology and the European League Against Rheumatism, will further facilitate studies on this disease.

Quantitative measurement of 18F-FDG PET/CT uptake reflects the expansion of circulating plasmablasts in IgG4-related disease.

Objective: [18F]Fluorodeoxyglucose (18F-FDG) PET/CT is increasingly used to assess organ involvement and response to treatment in IgG4-related disease (IgG4-RD), but clear correlations between 18F-FDG uptake and disease activity have not been established yet. We aimed to correlate the intensity and distribution of 18F-FDG uptake with validated clinical, serological and immunological parameters of IgG4-RD activity. Methods: Twenty patients with active IgG4-RD underwent a baseline 18F-FDG PET/CT. Ten patients repeated 18F-FDG PET/CT after immunosuppressive treatments. 18F-FDG tissue uptake was measured using the standardized uptake value corrected for the partial volume effect (PVC-SUV) and the total lesion glycolysis (TLG) with (TLGtot+ln) and without (TLGtot-ln) lymph nodes. Disease activity was assessed by means of clinical parameters [IgG4-RD Responder Index (RI)], serological (ESR and CRP) and immunological (serum IgG4 and circulating plasmablasts) biomarkers. The enhanced liver fibrosis score was exploited as a biomarker for fibroblast activation. Results: Thirteen (65%) patients had two or more organs affected by IgG4-RD. All patients had active IgG4-RD as defined by a median IgG4-RD RI value of 9 (range 6-15; normal < 3). Serum IgG4 and plasmablasts were elevated in 85% of patients. Circulating plasmablasts positively correlated with PVC-SUV (P = 0.027), inversely correlated with TLGtot-ln (P = 0.023) and did not correlate with TLGtot+ln (P > 0.05). No statistically significant correlation was found between PVC-SUV or TLG and IgG4-RD RI, ESR, CRP, serum IgG4 or enhanced liver fibrosis score (P > 0.05). Clinical response to immunosuppressive therapies was associated with a consensual reduction of circulating plasmablasts, PVC-SUV, TLGtot+ln and TLGtot-ln values (P < 0.05 for all comparisons). Conclusions: 18F-FDG uptake of IgG4-RD lesions reflects immunological perturbations of the B cell compartment rather than fibroblast activation and extracellular matrix deposition. Conventional biomarkers of disease activity, namely IgG4-RD RI, ESR, CRP and serum IgG4 levels, do not appear to correlate with the radiometabolic activity of IgG4-RD lesions. In light of our results PET/CT represents a reliable instrument for assessing IgG4-RD activity, although lymph-node uptake deserves careful interpretation.

Janus kinase inhibitors effectively improve pain across different disease activity states in rheumatoid arthritis.

Pain remains one of the most difficult-to-treat domains in patients with rheumatoid arthritis (RA). In clinical trials, the Janus kinase inhibitors (JAKis) have demonstrated good efficacy in pain relief. Aim of our study was to evaluate the real-life effectiveness of JAKis in improving pain in patients with RA in different states of baseline disease activity. A monocentric prospective cohort of 181 RA patients starting treatment with JAKis was studied. Pain was evaluated on a 0-100 mm visual analogue scale (VAS). Clinically meaningful improvements over 24 weeks were defined as follows: proportion of patients achieving ≥ 30%, ≥ 50%, and ≥ 70% pain relief, and remaining pain ≤ 20 or ≤ 10 mm. Results were analysed after stratification for baseline inflammatory activity; patients with swollen joints and C-reactive protein ≤ 1 at treatment start were considered pauci-inflammatory. Proportion of patients who achieved ≥ 30%, ≥ 50% and ≥ 70% pain improvement at 24 weeks was 61.4%, 49.3% and 32.9%. Furthermore, 40.6% and 28.5% of the patients achieved thresholds of remaining pain equivalent to mild pain or no/limited pain. Pain improvements were more evident in patients naive to previous biologics, although nearly 30% of multiple failures achieved VAS ≤ 20 mm. No significant differences were observed in relation to monotherapy. Pauci-inflammatory patients at treatment start achieved good outcomes, with 40.4% experiencing ≥ 70% pain improvement, and 35.7% VAS ≤ 10 mm. JAKis show efficacy in pain relief in real life. The improvement of painful symptoms also in those patients with limited objective inflammation may open new perspectives on the management of difficult-to-treat RA.