Davis, John

Abstract Introduction The underlying immunopathogenesis of inflammatory arthritis (IA) immune-related adverse event (irAE) remains obscure. Unlike rheumatoid arthritis (RA), where autoantibodies and B cell dysfunction are central features, the contribution of humoral immunity to IA-irAE is unclear. Methods Here, we performed immunophenotyping of peripheral blood from IA-irAE patients, and compared them with seronegative RA patients, ICI-treated patients without irAE, and healthy controls. Results IA-irAE was marked with increased cytotoxic gene expression and metabolic activation in T cells, and reduced CXCR3 and CCR6 expression in CD4+ T cells. Contrary to seronegative RA, IA-irAE patients displayed no significant elevation in autoantibody levels or atypical CD11c+CD21⁻ B cells. IA-irAE was further characterized by elevated levels of IL-6, IL-12, and type I IFN, which correlated with the T cell activation phenotypes. Conclusion Altogether, our findings define IA-irAE as a disease with certain immunological features distinctive from RA, representing a potentially T cell driven, autoantibody-independent autoimmunity. These results offer insights into immune tolerance breakdown and therapeutic targeting in irAEs. Funding Source National Institute of Arthritis and Musculoskeletal and Skin Diseases Mark E. and Mary A. Davis Initiative in Rheumatoid Arthritis Research Mayo Foundation for Medical Education and Research Topic Categories Basic Autoimmunity (BA)

Objective Since comorbidities such as autoimmune diseases may be associated with rheumatoid arthritis (RA) risk, we hypothesized that a family history of these other conditions might also predict RA. Therefore, we aimed to determine the association between family history of 79 comorbidities and RA. Methods This case–control study identified 821 cases of RA in the Mayo Clinic Biobank (positive predictive value 95%) and matched 3 controls to each case based on age, sex, recruitment year, and location. Patients self reported family history and characteristics (adjusted). Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for RA risk according to the presence of family history for each comorbidity, adjusted for body mass index, race, and smoking. Results Family history of several conditions was associated with developing RA, including rheumatic autoimmune diseases (OR adj 1.89 [95% CI 1.41–2.52]), pulmonary fibrosis (OR adj 2.12 [95% CI 1.16–3.80]), inflammatory bowel disease (OR adj 1.45 [95% CI 1.05–1.98]), hyper/hypothyroidism (OR adj 1.34 [95% CI 1.10–1.63]), and obstructive sleep apnea (OR adj 1.28 [95% CI 1.05–1.55]). Parkinson’s disease and type 2 diabetes mellitus were associated with a statistically decreased risk of RA that did not reach the prespecified significance threshold of P < 0.01 (OR adj 0.70 [95% CI 0.49–0.98] and OR adj 0.81 [95% CI 0.67–0.97], respectively). Analyses among 143 cases of incident RA were similar and also suggested an association with a family history of autism (OR 10.5 [95% CI 2.51–71.3]). Conclusion Family history of several autoimmune and nonautoimmune comorbidities was associated with increased risk of RA, providing an opportunity to identify novel populations at risk for RA.