This technology includes the use of genetic markers to predict the response of patients, particularly children with systemic juvenile idiopathic arthritis (sJiA), to anakinra treatment. Anakinra is a human recombinant IL-1 RA used in treating sJiA, a severe childhood inflammatory disease where early and effective treatment is essential for better long-term outcomes. Through the analysis of 38 children with sJiA treated with anakinra, specific sJiA-associated SNPs (single nucleotide polymorphisms) were identified as predictors of therapeutic failure, with a significant odds ratio of 17.3. This finding suggests that these genetic markers could be useful in predicting treatment responses not only in sJiA but also in adult-onset Still's disease and other autoinflammatory diseases where anakinra is used. Furthermore, this biomarker may extend its utility to predicting responses to other interleukin-1 directed therapies, such as canakinumab and rilonacept. As the only identified biomarker for forecasting both success and failure of anakinra treatment in systemic arthritis, its potential application lies in guiding initial therapeutic decisions in patients with systemic arthritis, encompassing both systemic juvenile idiopathic arthritis and adult-onset Still's disease.