The landscape of innate and adaptive immune cell subsets in patients with adult-onset Still’s disease

Abstract Objective Adult-onset Still’s disease (AOSD) is a systemic autoinflammatory disorder. The understanding of the changes in adaptive immune cells and the crosstalk between innate and adaptive immune systems in AOSD is limited. This study aimed to examine the peripheral immune cell composition and inflammatory protein levels in AOSD patients. Methods Twenty-nine active AOSD patients were enrolled. Flow cytometry was used to analyse the cell populations in peripheral blood. Antibody chips were utilized to detect the protein expression profile in serum. Results In active AOSD patients, there was an increase in the percentage of classical and non-classical monocytes among peripheral blood mononuclear cells. The proportion of natural killer (NK) cells decreased, with an increase in CD56dim NK1 cells and a decrease in CD56bright NK2 cells compared with healthy controls (HCs). The percentage of naïve central memory T cells was decreased, while the percentage of effector and effector memory T cells was increased among adaptive lymphocytes. The proportion of naïve B and memory B cells was decreased, while plasma cells were increased in AOSD patients, indicating activation of the adaptive immune system. Additionally, the serum levels of 40 proteins were elevated in AOSD patients, primarily involved in cytokine–cytokine receptor interaction, inflammatory response and regulation of mitogen-activated protein kinase cascade. Conclusion Our findings showed the activation of the innate and adaptive immune system in AOSD. The protein–protein interaction analysis suggested potential communication between innate and adaptive cell subsets. These findings provide new insights into the pathogenesis of the disease and the development of targeted therapies.