CLASSIFICATION OF THE LEUKEMIASCLASSIFICATION OF THE LEUKEMIAS

ACUTE• ACUTE MYELOID

LEUKEMIA

• ACUTE LYMPHOBLASTIC LEUKEMIA

CHRONIC• CHRONIC MYELOCYTIC

LEUKEMIA

• CHRONIC LYMPHOCYTIC LEUKEMIA

ACUTE LEUKEMIA CLASSIFICATIONACUTE LEUKEMIA CLASSIFICATION

• Morphology Morphology • CytochemistryCytochemistry• Immunophenotyping: Immunophenotyping: identifying antigens identifying antigens associated with cells (cell markersassociated with cells (cell markers))• Cytogenetics and molecular markersCytogenetics and molecular markers

ACUTE LEUKEMIA ACUTE LEUKEMIA CLASSIFICATION SYSTEMS CLASSIFICATION SYSTEMS

• FAB (French-American-British)

• MIC (Morphologic, Immunophenotypic and Cytogenetic)

• WHO

THE FRENCH-AMERICAN-BRITISH (FAB) THE FRENCH-AMERICAN-BRITISH (FAB) CLASSIFICATION OF THE ACUTE LEUKEMIASCLASSIFICATION OF THE ACUTE LEUKEMIAS

• Depends on a combination of MORPHOLOGIC, CYTOCHEMICAL

• for some categories, IMMUNOPHENOTYPIC characteristics

A Flow CytometerA Flow Cytometer

FAB CLASSIFICATIONFAB CLASSIFICATION

ACUTE MYELOID LEUKEMIAS

• M0: undifferentiated• M1: without maturation• M2: with granulocytic maturation• M3: promyelocytic• M4: myelomonocytic• M5: monocytic• M6: erythroleukemia• M7: megakaryoblastic

AML- FAB classificationAML- FAB classificationMYELOID /

GRANULOCYTIC LINEAGE• M0• M1• M2• M3

• MONOCYTIC +/- GRANULOCYTIC

• M4• M5

ERYTHROID• M6

MEGAKARYOCYTIC• M7

• CHRONIC MYELOID LEUKEMIA

CML: BLOOD SMEARCML: BLOOD SMEAR

CML-BMCML-BM

CML: BLOOD SMEARCML: BLOOD SMEAR

CML CML (courtesy www)(courtesy www)

CML BASOPHILSCML BASOPHILS

CML ; MARROWCML ; MARROW

ACUTE LEUKEMIAACUTE LEUKEMIA

FAB CLASSIFICATIONFAB CLASSIFICATION

ACUTE LYMPHOBLASTIC LEUKEMIAACUTE LYMPHOBLASTIC LEUKEMIA• L1L1: Uniform small size, high N/C ratio, regular nuclear

margin, inconspicuous nucleoli

• L2L2: Heterogeneous large and smaller cells, variable cytoplasm and nuclear margin, prominent nucleoli

• L3L3: Large cells, deeply basophilic and vacuolated cytoplasm, prominent nucleoli

ACUTE LEUKEMIA- BLASTSACUTE LEUKEMIA- BLASTS

Acute leukemia (courtesy www)Acute leukemia (courtesy www)

                 

AML- BLASTS WITH AUER RODSAML- BLASTS WITH AUER RODS

Myeloperoxidase reaction in blastsMyeloperoxidase reaction in blasts

                                                               

        

AML: CAEAML: CAE

ANAE [AML-M7]ANAE [AML-M7]

AML: AUER RODSAML: AUER RODS

PAS [ALL]PAS [ALL]

AML-M1AML-M1 (courtesy www) (courtesy www)

CYTOCHEMISTRY: REACTIONS IN BLASTSCYTOCHEMISTRY: REACTIONS IN BLASTS

AML• Myeloperoxidase +• Sudan Black +• Chloroactate esterase +• Nonspecific esterase + (M4, M5)• Periodic acid-Schiff - (+ in M6)• Acid phosphatase + (M4,M5,M6)

ALL - - - - + (40-60%cases) + (T-ALL)

IDENTIFYING BLASTS: OTHER CHARACTERISTICSIDENTIFYING BLASTS: OTHER CHARACTERISTICS

• IMMUNOLOGICAL: flow cytometry for ANTIGENS immunohistochemistry

• MOLECULAR: PCR, southern blotting for Ig AND TCR genes

• CYTOGENETIC for chromosomal abnormalities

• ELECTRONMICROSCOPIC

• IMMUNOLOGICAL (ANTIGENIC) MARKERS:

• IMMUNOPHENOTYPE determined by IMMUNOFLOWCYTOMETRY and/or IMMUNOHISTOCHEMISTRY

MYELOID MARKERSMYELOID MARKERS

• Myeloperoxidase• CD13, CD33• CD 11 b/c, CD14, CD15

IMMUNOPHENOTYPE: IMMUNOPHENOTYPE: CELL MARKERS (ANTIGENS)CELL MARKERS (ANTIGENS)

LYMPHOID

• B-LINEAGE- CD79a, CD22, µ chain, CD19, CD10 TdT

• T-LINEAGE- CD3 CD2, CD5, TdT, CD7

CLLCLL• Usually, lymphocytes are > 10 x 109/l with

involvement of bone marrow

• A diagnosis of CLL is possible with lower counts if morphology and immunophenotype are consistent with CLL

• A diagnosis of SLL but not CLL can be made histologically in the absence of BM or blood involvement

• The pattern of marrow infiltration is a guide to prognosis

CLL CLL

IMMUNOPHENOTYPE

• Weak/dim IgM or IgM and IgD• CD5, CD19• CD10-, cyclin D1-

CLL- LYMPHOCYTESCLL- LYMPHOCYTES

CLL- (courtesy www)CLL- (courtesy www)

PRACTICAL USES OF CLASSIFYINGPRACTICAL USES OF CLASSIFYING

• APPROPRIATE THERAPY

• PROGNOSTICATION

• IDENTIFICATION OF MINIMAL RESIDUAL DISEASE