Marked variations in cytokine levels and survival outcomes were observed, with the MN-HLH cohort exhibiting the highest levels of inflammatory markers (eg, median TNF-α, 105 pg/mL [IQR, 38-201 pg/mL] for MN-HLH vs 23 pg/mL [IQR, 17-42 pg/mL] for COVID-CS) and lowest fibrinogen and albumin levels. This evidence concerns the gene TNF and hemophagocytic syndrome.