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.

Environmental triggers for connective tissue disease: the case of COVID-19 associated with dermatomyositis-specific autoantibodies.

PURPOSE OF REVIEW: The aim of the present review is to analyze the link between autoimmune diseases and environmental factors, in particular severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (COVID-19) as it shares numerous features with the interstitial lung disease associated with connective tissue diseases positive for rare autoantibodies directed at highly specific autoantigens (i.e., MDA5 and RIG1) among the intracellular sensors of SARS-CoV-2 in the innate response against viruses. RECENT FINDINGS: As shown in recent publications and in our original data, specific autoantibodies may be functionally relevant to COVID-19 infection. We evaluated sera from 35 hospitalized patients with COVID-19 to identify antinuclear antibodies and autoantibodies directed against specific antigenic targets, and we identified anti-nuclear antibodies (ANA) in 20/35 of patients with COVID-19 (57%), in patients with need for supplemental oxygen (90% vs. 20% in ANA-negative cases; P < 0.0001). In 7/35 COVID-19 sera, we detected anti-MJ/NXP2 (n = 3), anti-RIG1 (n = 2), anti-Scl-70/TOPO1 (n = 1), and anti-MDA5 (n = 1), overall associated with a significantly worse pulmonary involvement at lung computerized tomography scans. Eleven (31%) patients were positive for antibodies against the E2/E3 subunits of mitochondrial pyruvate dehydrogenase complex. SUMMARY: Viral infections such as COVID-19 are associated with ANA and autoantibodies directed toward antiviral signaling antigens in particular in patients with worse pulmonary involvement.

Lymphocyte modulation by tofacitinib in patients with rheumatoid arthritis.

Tofacitinib is an oral small molecule targeting the intracellular Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathways approved for the treatment of active rheumatoid arthritis (RA). We investigated the effects of tofacitinib on the response of RA lymphocytes to B and T cell collagen epitopes in their native and post-translationally modified forms. In particular, peripheral blood mononuclear cells (PBMCs) from patients with RA and healthy subjects were cultured with type II collagen peptides (T261-273, B359-369, carT261-273, citB359-369) or with phorbol myristate acetate (PMA)/ionomycin/CD40L in the presence or absence of 100 nM tofacitinib for 20 h and analyzed by fluorescence activated cell sorter (FACS). Cultures without brefeldin A were used for cytokine supernatant enzyme-linked immunosorbent assay (ELISA) analysis. Tofacitinib down-regulated inflammatory cytokines by stimulated B [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] and T [interferon (IFN)-γ, IL-17 or TNF-α] cells in the short term, while a significant reduction of IL-17 and IL-6 levels in peripheral blood mononuclear cell (PBMC) supernatant was also observed. IL-10 was significantly reduced in collagen-stimulated B cells from patients with RA and increased in controls, thus mirroring an altered response to collagen self-epitopes in RA. Tofacitinib partially prevented the IL-10 down-modulation in RA B cells stimulated with collagen epitopes. In conclusion, the use of tofacitinib exerts a rapid regulatory effect on B cells from patients with RA following stimulation with collagen epitopes while not reducing inflammatory cytokine production by lymphocytes.

Rheumatoid factor and anti-citrullinated peptide antibodies in the general population: hepatitis B and C virus association and 15-year-risk of rheumatoid arthritis.

OBJECTIVES: The study aimed to determine the prevalence of rheumatoid factor (RF) and anti-citrullinated peptides (ACPA), to estimate the association with hepatitis B (HBV) or C (HCV) virus infections and the 15-year risk of developing RA in a large cohort from a Northern Italian region. METHODS: In 1998, 15,907 subjects between the ages of 18 and 75 were randomly selected 1:4 for HBV and HCV testing; more recently, we tested a subgroup of sera for RF (n=2196) and ACPA (n=2525). Administrative databases were searched after 15 years for incident RA diagnoses occurring between 1998 and 2013. RESULTS: RF was positive in 8.1% of cases with 10% of RF-positive subjects having HBsAg (p=0.004) and 9% anti-HCV. ACPA were detected in 4.8% of subjects with 5% of the ACPA-positive subjects having HBsAg and 5.9% anti-HCV. Older subjects had higher positivity rates for both RF and ACPA. HBsAg and anti-HCV were detected in 5.5% and 4.3% of sera, respectively. Over 15 years, 10 RA cases were recorded (9 women, median age at diagnosis 52 years) with RF previously positive in 2/10 and ACPA in 5/10 cases. RF and ACPA were associated with relative risks for developing RA of 5.7 (adjusted for HBsAg status; 95% CI 1.2-26.3) and 13.2 (95% CI 3.8-46.3), respectively. CONCLUSIONS: Our data in a large cohort from an unselected general population confirm a higher risk of RA development associated with ACPA compared to RF. HBV exposure correlates with RF but not with ACPA positivity.

Rheumatoid Factors in Hepatitis B and C Infections: Connecting Viruses, Autoimmunity, and Cancer.

BACKGROUND: Serum rheumatoid factors are autoantibodies of different isotypes directed against the Fc fraction of immunoglobulin G (IgG) and represent paradigmatic autoantibodies that have been largely used in clinical practice for decades. Traditionally IgG has been associated with rheumatoid arthritis and more recently included also in the classification criteria for SjÓ§gren's syndrome. Researchers have established that rheumatoid factors are positive in a variety of infectious, autoimmune, and neoplastic disorders, thus requiring a comprehensive evaluation of seropositive patients. Of note, hepatitis B and C viruses represent a crossroad that includes the high rheumatoid factor seroprevalence and chronic inflammatory disease, as well as progression to non-Hodgkin's lymphomas. Chronic antigen stimulation is the likely common ground of these processes and rheumatoid factors may represent mere bystanders or drivers of pathology. Mixed cryoglobulinemia and lymphoproliferative disease are prime examples of the deleterious effects of rheumatoid factor-B cell activity, possibly associated with hepatitis B and C. More importantly, they show a clear association in a physiological host response to infection, chronic inflammation, and the slide toward autoimmunity and malignancy. The association between hepatitis B and C infections and the appearance of serum rheumatoid factors is further supported by prevalence data, which support a coexistence of these markers in a significant proportion of cases, with viral infections being frequent causes of rheumatoid factors in patients without a rheumatic condition. We provide a comprehensive overview of the known connections between hepatitis B and C infections and rheumatoid factors.

Interleukin-17 and innate immunity in infections and chronic inflammation.

Interleukin 17 (IL-17) includes several cytokines among which IL-17A is considered as one of the major pro-inflammatory cytokine being central to the innate and adaptive immune responses. IL-17 is produced by unconventional T cells, members of innate lymphoid cells (ILCs), mast cells, as well as typical innate immune cells, such as neutrophils and macrophages located in the epithelial barriers and characterised by a rapid response to infectious agents by recruiting neutrophils as first line of defence and inducing the production of antimicrobial peptides. Th17 responses appear pivotal in chronic and acute infections by bacteria, parasites, and fungi, as well as in autoimmune and chronic inflammatory diseases, including rheumatoid arthritis, psoriasis, and psoriatic arthritis. The data discussed in this review cumulatively indicate that innate-derived IL-17 constitutes a major element in the altered immune response against self antigens or the perpetuation of inflammation, particularly at mucosal sites. New drugs targeting the IL17 pathway include brodalumab, ixekizumab, and secukinumab and their use in psoriatic disease is expected to dramatically impact our approach to this systemic condition.

The autoimmune landscape of Porto-sinusoidal vascular disorder: What the rheumatologist needs to know.

Porto-sinusoidal vascular disorder (PSVD) encompasses a group of vascular disorders characterized by lesions of the portal venules and sinusoids with clinical manifestations ranging from non-specific abnormalities in serum liver enzymes to clinically overt portal hypertension and related complications. Several reports have documented cases of PSVD in patients with systemic autoimmune conditions, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. It is of note that these diseases share specific pathophysiological features with PSVD, including endothelial dysfunction, vascular inflammation, and molecular signatures. This narrative review aims to summarize the current knowledge on the association between PSVD and systemic autoimmune diseases, emphasizing the importance of promptly recognizing this condition in the rheumatological practice, and highlighting the key aspects where further research is necessary from both pathogenic and clinical perspectives.

Autoantibodies, cutaneous subset and immunosuppressants contribute to the cancer risk in systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is associated with an increased risk of cancer. We aimed to assess the prevalence of cancer in our cohort and to explore possible associations with clinical, immunological and treatment characteristics. METHODS: Our retrospective monocentric cohort study of patients with SSc recorded prevalent and incident cases of malignancy, including those diagnosed within 3 years of the SSc onset (defined as cancer-associated scleroderma) and sought associations with the clinical characteristics and the serum autoantibody profiling performed using RNA and protein immunoprecipitation, Western-blot, immunoblot and ELISA at the time of SSc diagnosis, prior to any specific treatment. RESULTS: Among 290 patients with SSc, the overall prevalence of cancer was 20%, with 8% of cases being cancer-associated scleroderma. Both conditions were more frequent in elderly patients and in patients with positive anti-Ro52 or anti-U3-RNP. Cancer-associated scleroderma was significantly more prevalent among patients negative for both anti-centromere (ACA) and anti-topoisomerase-1 (TOPO1) antibodies, especially in the case of diffuse SSc. Immunosuppressants were not significantly associated with cancer. Patients triple negative for ACA, TOPO1 and anti-RNA polymerase III antibodies had a significantly higher risk of breast cancer. CONCLUSIONS: Cancer surveillance should be particularly careful in patients with diffuse SSc, increased age at disease onset and without classical SSc-related autoantibodies.