Autoinflammatory diseases (AIDs) are a group of abnormal inflammatory diseases mediated by innate immune cells with a certain hereditary susceptibility, including monogenic AIDs and polygenic AIDs. AIDs are characterized by various clinical manifestations, periodic attacks and intermittent symptom relief, multiple systems are often involved, and skin is one of the predominantly involved organs. Due to genetic diversity and uncertainty in AIDs, gene-based classification is unhelpful in clinical recognitoin and selection of therapeutic strategies. With in-depth study on the pathogenesis of AIDs, researchers have found overlapping inflammatory pathways in AIDs sharing common skin lesions, which may be treated with similar strategies. This review describes classification of AIDs according to features of skin lesions, summarizes commonalities in their immune mechanisms and histopathological features, and discusses possible effective treatment regimens and interventions, in order to facilitate the clinical diagnosis and treatment.

  Objective  To summarize the clinical manifestations, pathological features and gene mutation diversity of Blau syndrome/early-onset sarcoidosis.  Methods  We collected general data, clinical manifestations, and auxiliary examination results from 8 patients who were diagnosed of Blau syndrome/early-onset sarcoidosis and treated in our hospital from January 2011 to December 2022, and then summarized and analyzed their characteristics and diversity.  Results  Among the 8 patients, 4 were males and 4 were females. The onset age was 3 to 8 months old. Rash was the first symptom in 7 patients(87.5%). 6 patients(75.0%) had papules and erythema.3 cases(37.5%) had arthritis. 2 cases(25.0%) had uveitis and other eye inflammation. 4 cases (50.0%) also showed intermittent fever. 3 cases (37.5%) showed symptoms in nerve and respiratory system, and hypertension respectively. The skin histopathology of 8 patients showed non-caseous granuloma formation. In laboratory detection, CRP and TNF-α were significantly increased before treatment, while IL-6, IL-8, TNF-α and IL-2 receptor(IL-2R) were significantly decreased in 5 patients after glucocorticoid therapy. The results of genetic testing showed that 4 of the 7 patients had p.R334W(c.1000C > T) mutation, 1 had p.H313R(c.938A > G) and p.R471C(c.1411C > T)double mutation, and 1 had p.476_477del (c.1427_1429delcct).  Conclusions  Blau syndrome/early-onset sarcoidosis has significant features in clinical manifestations, histopathology and gene mutation, but it also has diversity.