Table 1. HLH-2004 criteria, 2016 MAS-sJIA (PRINTO) criteria, and HScore [8–10]

	HLH-20041)	2016 MAS-SJIA (PRINTO)1)	HScore (points)1)
Fever (°C)	≥ 38.5	-	38.4–39.4 (33); > 39.4 (49)
Organomegaly	SM	(Any two of the four criteria)	HM or SM (23); HSM (38)
Abnormal CBC	Cytopenia ≥ 2 lineages	Platelet counts ≤ 181,000 /μL	2 lineages (24); 3 lineages (34)
Elevated liver enzymes (U/L)	-	AST > 48	AST ≥ 30 (19)
Abnormal TG (mg/dL)	TG ≥ 265	TG > 156	133–354 (44); > 354 (64)
or fibrinogen (mg/dL)	or fibrinogen ≤ 150	Fibrinogen ≤ 360	≤ 250 (30)
Hyperferritinemia (ng/mL)	Ferritin ≥ 500	Ferritin > 684 (essential)	2,000–6,000 (35); > 6,000 (50)
Elevated sCD25 levels (U/mL)	sCD25 (sIL-2R) ≥ 2,400	-	-
Changes in NK cell function	Decreased NK cell activity	-	-
Hemophagocytosis	BM, liver, or lymph nodes	-	Present (35)
Known immunosuppression	-	-	Present (18)
Diagnosis	≥ 5/8 criteria	Hyperferritinemia + ≥ 2/4 criteria	HScore (points) ≥ 169

Patient in this study met five criteria of the six HLH-2004 criteria tested (i.e., sCD25 levels and NK cell activity were not tested) and all 2016 MAS-SJIA criteria. The patient’s HScore was 264 points.
HLH: hemophagocytic lymphohistiocytosis; MAS: macrophage activation syndrome; SJIA: systemic juvenile idiopathic arthritis; 2016 MAS-SJIA: the 2016 consensus criteria for MAS complicating SJIA; PRINTO: Paediatric Rheumatology International Trials Organisation; HScore, hemophagocytic syndrome diagnostic score; SM: splenomegaly; HM: hepatomegaly; HSM: hepatosplenomegaly; CBC: complete blood cell count; AST: aspartate aminotransferase; TG: triglycerides; sIL-2R: soluble interleukin-2 receptor; NK: natural killer; BM: bone marrow.