title: MBL or CLL: which classification best categorizes the clinical course of patients with an absolute lymphocyte count >or= 5 x 10(9) L(-1) but a B-cell lymphocyte count <5 x 10(9) L(-1)?
abstract: To eliminate overlap with monoclonal B-cell lymphocytosis (MBL), some have proposed basing the diagnosis of chronic lymphocytic leukemia (CLL) on B lymphocyte count rather than absolute lymphocyte count (ALC). Such criteria should be based, in part, on patient outcomes. We evaluated the clinical implications of the proposed re-classification in 112 consecutive, newly diagnosed, Rai stage 0 patients. The new criteria would have changed the diagnosis from CLL to MBL in 47/112 (42%) patients. There was no difference in time to treatment (TTT) between those classified as MBL and CLL under the new criteria. In contrast, CD38 predicted TTT (p=0.02) regardless of the proposed new classification. Molecular characteristics of the leukemic clone are a better predictor of progression than an arbitrary ALC or B lymphocyte count threshold.
authors.affiliation: Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, United States.
authors.forename: Tait D
authors.initials: TD
authors.lastname: Shanafelt
authors.forename: Neil E
authors.initials: NE
authors.lastname: Kay
authors.forename: Tim G
authors.initials: TG
authors.lastname: Call
authors.forename: Clive S
authors.initials: CS
authors.lastname: Zent
authors.forename: Diane F
authors.initials: DF
authors.lastname: Jelinek
authors.forename: Betsy
authors.initials: B
authors.lastname: LaPlant
authors.forename: William G
authors.initials: WG
authors.lastname: Morice
authors.forename: Curtis A
authors.initials: CA
authors.lastname: Hanson
mesh_terms: D000368:Aged; D001402:B-Lymphocytes / Q000473:pathology*; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000145:classification* / Q000473:pathology / Q000628:therapy; D018655:Lymphocyte Count; D008218:Lymphocytosis / Q000145:classification* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015996:Survival Rate; D013997:Time Factors