Based on literature data demonstrating their role in NK and T-cell mediated inflammation, we investigated a panel of serum markers as candidate adjuvants to diagnose CRS/MAS and IEC-HS, including soluble CD163, IL33R, CTLA-4, and CD80, and studied their trend in frozen sera collected at sequential time-points, before and after infusion. Here, IL1RL1 is linked to macrophage activation syndrome.