MF with B2 blood involvement (Sézary cell count ≥1000/μL OR ≥5% Sézary by morphology) — d...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-MF-SEZARY-LEUKEMIC`
Type	Red flag
Status	reviewed 2026-04-25 \| pending_clinical_signoff
Diseases	`DIS-MF-SEZARY`
Sources	`SRC-ESMO-CTCL-2024` `SRC-NCCN-BCELL-2025`

Red Flag Origin

Definition	MF with B2 blood involvement (Sézary cell count ≥1000/μL OR ≥5% Sézary by morphology) — defines Sézary syndrome / IVA1 stage; routes to systemic therapy with mogamulizumab preference
Clinical direction	intensify
Category	high-risk-biology
Shifts algorithm	ALGO-MF-SEZARY-1L

Trigger Logic

{
  "any_of": [
    {
      "finding": "BIO-SEZARY-COUNT",
      "value": "B2"
    },
    {
      "finding": "sezary_count_b2",
      "value": true
    },
    {
      "finding": "sezary_syndrome",
      "value": true
    }
  ],
  "type": "biomarker"
}

Notes

B2 = leukemic phase, automatic upstaging to IVA1 regardless of skin T-stage. MAVORIC trial subset showed mogamulizumab response highest in B2 (blood compartment most uniform CCR4+). Sézary syndrome variant always advanced — skin-directed alone insufficient.

MF with B2 blood involvement (Sézary cell count ≥1000/μL OR ≥5% Sézary by morphology) — d...

Red Flag Origin

Trigger Logic

Notes

Used By

Algorithms

Indications