Dynamics of clinical and laboratory parameters in pHLH patients during emapalumab treatment. (A) H-score decrease in low- and high-dose emapalumab groups. H-score of 90 was used as a cutoff for active disease. (B) Dynamics of CXCL9 level on emapalumab therapy. (C) Dynamics of dexamethasone dose reduction on emapalumab therapy. (D) Dynamics of HLH activity in P6, who had a relapse of the disease after emapalumab discontinuation and quickly responded to emapalumab treatment reinstitution.