She had complete resolution of sJIA symptoms including marked improvement in her lung disease along with normalization of serum interleukin-18 and CXCL9 levels.<h4>Conclusion</h4>The use of emapalumab followed by allo-HSCT could help achieve a complete response in refractory cases of sJIA complicated by MAS who have failed standard treatment. Here, CXCL9 is linked to systemic-onset juvenile idiopathic arthritis.