Table 1 Characteristics and manifestations that conform to the diagnostic criteria

Case 1

9-year- old/ girl

Clinical symptoms: Fever, lymphadenopathy Laboratory investigations: leukopenia

Pathology: KFD

Immunohistochemistry:

EBER(-), ALK1(-),CD10(-), CD20(-), CD21(-), CD30(-), CD34(-), CD38(-), CD4( +), CD8( +), CK(-), KP-1( +), LCA( +), Lys( +), MUM1(-), PAX5(-), PGM1( +)

ANA at a titer of 1:320

Fever > 38.3℃ (score 2)

2. Leukopenia, thrombocytopenia (score 4)

alopecia, rash (score 4)

Pleural or pericardial effusion (score 5)

4. Low C3 and low C4 (score 4)

Total score: 19

Clinical criteria:

1. Fever with T > 38℃

2. Hepatomegaly and splenomegaly

3. Central nervous system symptoms (dim)

Laboratory criteria:

Thrombocytopenia (minimum number: 3 × 10^9/L), anemia (minimum number: 56 × 10^9/L)

AST (maximum number: 652 U/L)

LDH (maximum number: > 8600 U/L)

SF (maximum number: > 6000 ug/L)

FIB (minimum number: 0.62 g/L)

Case 2

10-year- old/ girl

Clinical symptoms: Fever, lymphadenopathy Laboratory investigations: leukopenia

Pathology: Necrotizing lymphadenitis

Immunohistochemistry:

LCA( +), CD20( +),PAX5( +), CD3( +), CD2( +), CD30( +), EMA( +), CD10( +), CD15( +), CD34( +), TdT(-), Ki-67( +), CD21( +), CD38( +), ALK(-), CD68( +)

ANA at a titer of 1:1000

Fever (score 2)

Leukopenia, thrombocytopenia, Coombs’

test positive (score 4)

Subacute discoid lupus (score 4)

Low C3 (score 3)

Anti-Sm antibody positive (score 6)

Total score: 19

Clinical criteria:

1. Fever with T > 38℃

Laboratory criteria:

Thrombocytopenia (minimum number: 101 × 10^9/L), leukopenia (minimum number: 2.15 × 10^9/L)

3. AST (maximum number: 59 U/L)

4. LDH (maximum number: 3156 U/L)

5. SF (maximum number: 1420.6 ug/L)