Systemic vasculitis is an extremely important and highly heterogeneous group of rheumatologic diseases. Compared to other rheumatic immune diseases, the current level of understanding and management of vasculitis is still lagging behind, and an important reason for this is the lack of non-invasive and practical biomarkers for early diagnosis, disease activity and outcome assessment. Large-vessel vasculitis Large-artery vasculitis Dutch studies have shown the importance of using positron emission tomography (PET)-CT to evaluate patients with a diagnosis of large-artery vasculitis (TA) but with normal ESR and C-reactive protein (CRP) levels, showing a significant increase in the uptake of fluorodeoxyglucose (FDP) at the site of involvement. Studies in Brazil also suggest that FDG uptake and interleukin (IL)-6 and metalloproteinase (MMP)-3 levels on PET-CT can be important tools for assessing the activity of TA disease. After screening and multiple correlation analysis of 21 candidate cytokines, French scholars found that elevated levels of cytokines such as IL-21 and IL-17A are highly correlated with TA disease activity, and IL-21 is a key upstream factor promoting the dominant differentiation of helper lymphocytes (Th)1 and Th17 and the upregulation of FoxP3 expression; therefore, IL-21 may be a therapeutics study of TA The important target of TA. Other UK scholars have identified a significant increase in neutrophil membrane-linked protein (Annexin-A1) expression as a potential specific novel biomarker for the diagnosis of giant cell arteritis (GCA); studies by German scholars suggest that positive antiferritin heavy chain antibodies could be a marker for the diagnosis of TA and GCA. The role of endothelial damage in the pathogenesis of Kawasaki disease (KD) is crucial, and the fibroblast growth factor (FGF)23/FGF23 receptor complex and its cofactor Klotho protein have important roles in regulating phosphorus homeostasis, bone mineralization and controlling vascular damage and atherosclerosis in vivo. Klotho protein is expressed in many tissues, including the vascular system, and is a key protein with vascular protective effects. Studies by Italian scholars suggest that serum Khloto protein levels are significantly reduced in KD patients, and it may be an important new marker of vascular injury in KD patients. Small vessel vasculitis Wegener’s granulomatosis The disease is now known as granulomatosis with polyangiitis (GPA). A study by Dutch scholars found that the expression level of IL-21-producing follicle-like helper T cells (TFH) in the blood circulation was significantly increased in GPA patients who were positive for anti-neutrophil cytoplasmic antibodies (ANCA). This suggests that TFH cells have an important role in the immunopathogenesis of GPA and may become an important target in GPA therapeutics research. ANCA-associated vasculitis In a study conducted by the RAVE Study Group comparing the efficacy of glucocorticoids in combination with rituximab or cyclophosphamide, respectively, in the treatment of ANCA-associated vasculitis (AAV), investigators followed up on the traditional biomarkers ANCA and its subclasses [proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA], ESR and CRP, in addition to 28 potentially significant candidate serum proteins, including cytokines, tissue damage and repair factors, chemokines, inflammatory and vascular damage factors, and soluble receptor proteins, were also determined by microarray microarray. Multiple regression analysis suggested that CXCL13 / BCA-1 and MMP-3 / TIMP-1 were expected to be novel markers of active AAV, while the poor correlation of ESR and CRP with the above indicators suggested that they were not ideal markers of active AAV. In Sweden, plasma mitochondrial DNA (mDNA) and nuclear DNA (nDNA) levels in patients with active AAV were measured by quantitative polymerase chain reaction (PCR), and the results showed that elevated mDNA levels are also one of the biomarkers of active AAV. Allergic granulomatous vasculitis Studies by Italian scholars have shown that elevated levels of IgG4 correlate with the activity of allergic granulomatous vasculitis (CSS) and the severity of its disease, and can be used as an indicator to differentiate it from other vasculitis (e.g., GPA). From the above, it is clear that many new cytokines and serum proteins will be promising indicators for the diagnosis and activity assessment of primary vasculitis, which may be more sensitive and specific than acute chronological reactors such as ESR/CRP, and are expected to be biomarkers for early diagnosis and therapeutic assessment of vasculitis and improve disease regression.