Long-term prognosis of 47 pediatric patients with Blau syndrome in China.

Objectives: Blau syndrome (BS) is a rare autoinflammatory disease characterized by a clinical triad of uveitis, dermatitis and arthritis. The aim of our study was to summarize organ involvement, predict disease prognosis and evaluate treatment response.

Methods: Clinical data of 47 Chinese children who were diagnosed with Blau syndrome in Beijing Children's hospital, Capital Medical University was retrospectively analyzed. Direct sequencing of NOD2 gene was performed by sanger sequencing. Data were analyzed through SPSS 21.0. A Bayesian network was constructed to integrate prediction algorithms of genetic mutations and clinical manifestations, exploring the complex relationship between genotype and phenotype through R (Version 4.4.1, R Core Development Team). P value < 0.05 was significant.

Results: The 47 patients included 26 males and 21 females. Median age of disease onset was 13.64 months, ranging from 1 to 51 months. At baseline, incidence of fever, arthritis, rash, dermatitis and uveitis were 34%, 93.6%, 72.3% and 31.9%. Nearly 30% patients (14 patients) presented with characteristic triad. Incidence of vasculitis and interstitial lung disease were 27.7% and 17.0%, respectively. Inflammatory indices (e.g., erythrocyte sedimentation rate and C reactive protein) were above normal range. Twelve different NOD2 mutations were identified. R334Q was associated with arthritis, rash, uveitis and fever, whereas R334W was associated with arthritis, rash and fever. Approximately 95.7% patients (45 patients) were treated with combination of prednisolone and methotrexate and 42.6% patients (20 patients) were treated with tumor necrosis factor inhibitors. At the most recent follow-up visit, 34 patients (72.3%) achieved disease control. Patients treated with TNF-α inhibitors had a higher remission rate.

Conclusions: Clinical manifestations of Blau syndrome in this study were various. TNF-α inhibitors were effective in inducing remission rate of Blau syndrome.