| Required criteria | Chronic (>6 months), nonmalignant, noninfectious lymphadenopathy and/or splenomegaly Elevated CD3+αβ+CD4-CD8- DNT cells (>1.5% of total lymphocytes or >2.5% of CD3+ lymphocytes) with normal or elevated lymphocyte counts |
| Accessory criterion | |
| Primary | Defective FAS-induced lymphocyte apoptosis Somatic or germline pathogenic mutation in FAS, FASL, FADD or CASP10 |
| Secondary | Elevated plasma sFASL levels (>200 pg/ml) Elevated plasma IL-10 levels (>20 pg/ml) Elevated serum or plasma Vitamin B12 levels (>1500 pg/mL) Typical immunohistopathology findings (paracortical T cell hyperplasia) Autoimmune cytopenias (hemolytic anemia, thrombocytopenia or neutropenia) Elevated IgG levels (polyclonal hypergammaglobulinemia) Family history of a non-malignant or lymphoma-associated non-infectious lymphoproliferation with or without autoimmunity |
| Definitive diagnosis | Both required criteria plus one primary accessory criterion |
| Probable diagnosis | Both required criteria plus at least one secondary accessory criterion |
| Required criteria | Chronic (>6 months), nonmalignant, noninfectious lymphadenopathy and/or splenomegaly Elevated CD3+αβ+CD4-CD8- DNT cells (>1.5% of total lymphocytes or >2.5% of CD3+ lymphocytes) with normal or elevated lymphocyte counts |
| Accessory criterion | |
| Primary | Defective FAS-induced lymphocyte apoptosis Somatic or germline pathogenic mutation in FAS, FASL, FADD or CASP10 |
| Secondary | Elevated plasma sFASL levels (>200 pg/ml) Elevated plasma IL-10 levels (>20 pg/ml) Elevated serum or plasma Vitamin B12 levels (>1500 pg/mL) Typical immunohistopathology findings (paracortical T cell hyperplasia) Autoimmune cytopenias (hemolytic anemia, thrombocytopenia or neutropenia) Elevated IgG levels (polyclonal hypergammaglobulinemia) Family history of a non-malignant or lymphoma-associated non-infectious lymphoproliferation with or without autoimmunity |
| Definitive diagnosis | Both required criteria plus one primary accessory criterion |
| Probable diagnosis | Both required criteria plus at least one secondary accessory criterion |