Spondyloarthritis (SPA).It is a group of chronic inflammatory and disabling rheumatic immune diseases mainly affected by axial bones and/or peripheral joints, which are more common in young men, with strong clinical heterogeneity, in addition to joint involvement, psoriasis, inflammatory bowel disease, ophthalmitis, etc., often accompanied by cardiovascular and cerebrovascular diseases and other comorbidities.
Depending on the main area affected, SPA can also be divided into:Central axis type and peripheral type。Axial forms include ankylosing spondylitis (AS) and radiographically negative axial SPA (NR-AXSPA), while peripheral types include psoriatic arthritis (PSA), inflammatory bowel arthritis, reactive arthritis, undifferentiated SPA, and juvenile SPA. Axial SPA with sacroiliac joint abnormalities on plain radiographs is AS, otherwise NR-AXSPA.
Different forms of SPA share a variety of common clinical features, the most prominent being inflammation of the axial joints (especially the sacroiliac joints), asymmetric oligoarthritis (especially the lower extremities), dactylitis (sausage toes), and enthesitis (inflammation of the bone attachments of ligaments or tendons). Patients with SPA have a higher rate of HLA-B27 positivity and a higher chance of sacroiliitis on radiographs or MRIs compared with the general population. Early diagnosis and early standardization** are the keys to delay the progression of SPA disease and improve prognosis. Before the advent of targeted drugs, non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs (DMARDS) were mainly used in SPAs. With the deepening of the research on the pathogenesis of SPA, researchers have found that some inflammatory cytokines or pathways play an important role in the pathogenesis of SPA. Drugs that target cytokines or pathways have the characteristics of rapidly improving symptoms, delaying disease progression, improving quality of life, and reducing disability. 
At present, targeted drugs that have been approved for **SPA at home and abroad include biological targeted drugs and synthetic small molecule targeted drugs. Biologically targeted drugsThese include tumor necrosis factor (TNF)-inhibitors (e.g., etanercept, infliximab, adalimumab, golimumab, certolizumab), interleukin (IL)-12 23 inhibitors (e.g., ustekinumab, guselkumab), IL-17A inhibitors (e.g., secukinumab, ixekizumab), and selective T-cell costimulatory modulators (e.g., abatacept). Synthesis of small molecule targeted drugsThese include Janus kinase (JAK) inhibitors (e.g., tofacitinib, upadatinib, etc.) and phosphodiesterase 4 inhibitors (e.g., apremilast). Different frontal targeted drugs have different mechanisms of action, so some basic contents need to be clarified before taking drugs. At present, it is recommended to use SPA targeted drugs for the following groups: the effect is still not good after at least the maximum dose of NSAIDs** for several weeks; Active after at least one NSAIDS** month; Patients with SPA who are intolerant to NSAIDS, or who are still active despite NSAIDS** but enthesitis and axial symptoms; For patients with prominent peripheral joint disease, no or mild axial joint disease, DMARDS drugs (eg, sulfasalazine, methotrexate, etc.) may improve symptoms if NSAIDs** are inadequate. If disease control is poor, a switch to a targeted drug may be considered**. If psoriasis lesions in PSA patients are extensive and severe, especially when special parts such as the head and face, fingernails and *** are involved, targeted drugs can be used at the initial time; If patients with PSA have predominantly peripheral joint involvement, enthesitis, or prominent axial symptoms, targeted drugs can be used initially.
In addition, because the use of targeted drugs may increase the risk of infection and activate latent infection, infection should be evaluated and screened for infection before the use of targeted drugs. Including hepatitis B, hepatitis C, tuberculosis, etc.