Rheumatoid factor (RF) is the first autoantibody identified in rheumatoid arthritis (RA) which targets the fragment crystallizable (Fc) region of immunoglobulin (Ig) G. Although IgM isotype is predominant, other Ig isotypes, including IgG and IgA, also exist. While RF is not specific to RA, it remains a valuable serological test for diagnosing the disease, as evidenced by its inclusion in the 2010 classification criteria for RA based on elevated serum RF levels. RF is also associated with RA severity, including joint damage and extra-articular manifestations, serving as a poor prognostic factor and aiding in the identification of difficult-to-treat RA. Recent studies have demonstrated that high serum RF levels are associated with a reduced response to tumor necrosis factor (TNF) inhibitors. In contrast, anti-TNF antibodies lacking the Fc portion have shown stable efficacy in RA patients regardless of baseline RF levels. These findings reaffirm the clinical significance of RF measurement, 80 years after its initial discovery. This review explores the diagnostic and prognostic significance of RF and its impact on treatment selection in RA management.

With the aging of the population, malignancies are becoming common complications in patients with rheumatoid arthritis (RA), particularly in elderly patients. Such malignancies often interfere with RA treatment. Among several therapeutic agents, immune checkpoint inhibitors (ICIs) which antagonize immunological brakes on T lymphocytes have emerged as a promising treatment option for a variety of malignancies. In parallel, evidence has accumulated that ICIs are associated with numerous immune-related adverse events (irAEs), such as hypophysitis, myocarditis, pneumonitis, and colitis. Moreover, ICIs not only exacerbate pre-existing autoimmune diseases, but also cause de novo rheumatic disease–like symptoms, such as arthritis, myositis, and vasculitis, which are currently termed rheumatic irAEs. Rheumatic irAEs differ from classical rheumatic diseases in multiple aspects, and treatment should be individualized based on the severity. Close collaboration with oncologists is critical for preventing irreversible organ damage. This review summarizes the current evidence regarding the mechanisms and management of rheumatic irAEs with focus on arthritis, myositis, and vasculitis. Based on these findings, potential therapeutic strategies against rheumatic irAEs are discussed.

The varicella-zoster virus (VZV) is a human neurotropic herpes virus responsible for varicella and herpes zoster (HZ). Following primary infection in childhood, VZV manifests as varicella (chickenpox) and enters a period of latency within the dorsal root ganglion. A compromised cellular immune response due to aging or immunosuppression triggers viral reactivation and the development of HZ (shingles). Patients with autoimmune diseases have a higher risk of developing HZ owing to the immunodeficiency associated with the disease itself and/or the use of immunosuppressive agents. The introduction of new immunosuppressive agents with unique mechanisms has expanded the treatment options for autoimmune diseases but has also increased the risk of HZ. Specifically, Janus kinase (JAK) inhibitors and anifrolumab have raised concerns regarding HZ. Despite treatment advances, a substantial number of patients suffer from complications such as postherpetic neuralgia for prolonged periods. The adjuvanted recombinant zoster vaccine (RZV) is considered safe and effective even in immunocompromised patients. The widespread adoption of RZV may reduce the health and socioeconomic burdens of HZ patients. This review covers the link between VZV and autoimmune diseases, assesses the risk of HZ associated with immunosuppressant use, and discusses the benefits and risks of using RZV in patients with autoimmune diseases.

Type I interferons (IFN-I) are pivotal effectors of innate immunity and constitute a central axis of host defense against pathogens. Sensing of exogenous or endogenous nucleic acids by pattern-recognition receptors—exemplified by Toll-like receptors—triggers transcriptional induction of IFN-I. Engagement of the heterodimeric IFN-I receptor on nucleated cells reprograms cellular states via canonical Janus kinase–signal transducer and activator of transcription (JAK–STAT) signaling as well as STAT-independent, noncanonical pathways. This axis is tempered by multilayered regulatory mechanisms, including epigenetic remodeling, and important aspects remain incompletely defined. Dysregulation of IFN-I activity underlies diverse autoimmune disorders, notably systemic lupus erythematosus, wherein IFN-responsive gene signatures stratify disease endotypes, reflect disease activity trajectories, and predict therapeutic responsiveness. In recent years, therapeutic strategies targeting this pathway are now available: anti-IFN-I receptor therapy for systemic lupus erythematosus (SLE) and JAK inhibition for rheumatoid arthritis (RA) and giant cell arteritis (GCA). Altogether, a refined understanding of the IFN-I axis furnishes a pragmatic framework for patient stratification, response prediction, and mechanism-informed therapy design across immune-mediated diseases.

To determine the current retention rate of mepolizumab (MPZ) and identify factors associated with drug retention in patients with eosinophilic granulomatosis with polyangiitis (EGPA) in the Kansai multicentre cohort (REVEAL cohort). Sixty patients diagnosed with EGPA and treated with MPZ between December 2016 and June 2023 were enrolled. The clinical characteristics, including laboratory data, treatments administered, and disease course outcomes, were collected retrospectively. The patients were stratified into MPZ continuation (n = 53) and discontinuation (n = 7) groups, and drug retention was statistically compared using the log-rank test. The median age of patients was 54.5 years, with 55% females, and 33% antineutrophil cytoplasmic antibody-positive at disease onset. MPZ exhibited a retention rate of 78.7% after 5 years. The reasons for discontinuation included treatment of coexisting diseases, inadequate response, and remission. Patient characteristics at disease onset were comparable between the groups. Patients receiving immunosuppressants (IS) before MPZ introduction demonstrated significantly higher retention rates (P = 0.038). During the final observation, the MPZ continuation group had a lower vasculitis damage index score (P = 0.027). MPZ exhibited a high 5-year retention rate, particularly in patients requiring IS. This study implies that long-term use of MPZ may mitigate irreversible organ damage.

Giant cell arteritis (GCA) is a form of large vessel vasculitis that primarily affects older adults and forms granulomatous inflammation in the aorta and its major branches. Recent advances in immunology and multi-omics technologies have elucidated several key mechanisms involved in the pathogenesis of GCA, including immune checkpoint dysregulation, clonal hematopoiesis, and age-associated immune dysfunction. From the perspective of immune cell subsets, a diverse range of immune cells—including tissue-resident memory T cells, stem-like T cells, macrophage subsets, B cells, and myofibroblasts—play distinct roles in sustaining vascular inflammation and tissue remodeling. This review summarizes the latest immunopathological and omics-based insights into GCA, proposes potential therapeutic targets, and discusses future directions for precision medicine aimed at achieving sustained remission.