Normal & Leukaemic haematopoiesis 2010 Dr. Liu Te Chih Dept - PowerPoint PPT Presentation

Normal & Leukaemic haematopoiesis 2010 Dr. Liu Te Chih Dept of Haematology / Oncology National University Health Services Singapore

Use of Immunophenotyping today • Lineage assignment • Differentiation of reactive from leukaemic blasts • Detection of Minimal Residual Disease

1. Leukaemic cells are phenotypically aberrant Normal (PBSCH) Leukaemic CD34+ cells (red):

2. Detection Sensitivity: ~ 0.01% Diagnostic PR: 5% CR 40% - 20% 4% - 1% 0.4% - 0.1% TJ - M4 AML : Gated: CD34+ NG2/CD65/CD45/CD34 CD34+ blasts (yellow) CD34- blasts (red)

Excitation Optics focusing prisms lens fiber optic cables steering plate flow cell red laser blue laser violet laser 5

Immunophenotyping today • 8 Colour cytometers • Improved hardware sensitivity

Normal haematopoiesis Orkin, Cell 2008; 132:631

CD34+/90+/(Rho-lo)/lin- - frequency: 0.02 - 0.1% of BM nucleated cells

Normal haematopoiesis 38- CD34+/38-/90+/45RA-/ 10-/117+/FLT3R-/lin- CD34+/38-/90-/45RA-/ 10-/117+/FLT3R-/lin- 90- CD34+/90-/38+/117+/13+/33+/HLADR+/64- CD34+/90-/38+/117-lo/10+ (or 38+ /41a-/9-/FLT3R+/lin- 10+/IL7Ra+/ 7+)/FLT3R+/lin- CD123-lo/45RA- 117lo CD123-lo/CD45RA+ CD123-/CD45RA- Orkin, Cell 2008; 132:631

IMMUNOPHETOPYPIC CHARACTERIZATION OF IMMATURE / EARLY CD34 + HPC GATE OF CD34 + HPC Orfao, 2007

ERYTHROID & B-LYMPHOID DIFFERENTIATION IN BM GATE OF CD34 + HPC Orfao, 2007

Leukaemic situation

31yr Male SSC SSC Pancytopenia HLADR/117/45/34 FSC CD45 Green - Leuk blasts Cyan - Myeloblasts Grey - Lymphocytes Yellow - Neutrophils SSC CD117 Blue - Monocytes Pink - Eosinophils CD34 HLADR

SSC cMPO nTdt/cMPO/45/34 CD45 nTdt CD19/c79a/45/34 cCD79a CD7 cCD3/7/45/34 Green - Leuk blasts Cyan - Myeloblasts Grey - Lymphocytes CD19 cCD3 Pink - B-lymphocytes

CD10 CD7/10/19/34 CD19 CD38 CD38 CD71/38/123/34 Green - Leuk blasts Cyan- Myeloblasts (presumed) CD123 CD34

• Myeloblasts (10%) • Lymphoblasts (90%) - ? T or ?B • nuTdt+ / CD34+ • B-lineage: CD19+ / cyCD79a- / CD22- / 10+ • T-lineage: cyCD3- / CD7+

Phenotype: CD45-/34+/38-/123+/10+/19+/7dim/117-/HLADR+/nuTdt+/71- Lineage Negative: cy79a/cy22/cyMPO/cy3/4/8/56/light chain/41/42a CD34+/38-/90+/45RA-/ 10-/FLT3R-/lin- CD34+/38-/90-/45RA-/ 10-/FLT3R-/lin- CD34+/90-/38+/117-lo/10+ (or 7+)/FLT3R+/lin- CD34+/90-/38+/117+/13+/33+/HLADR+/64- /41a-/9-/FLT3R+/lin- CD123-lo/45RA- CD123-lo/CD45RA+ CD123-/CD45RA- Orkin, Cell 2008; 132:631

Ph+ ( bcr-abl p190+) Acute Lymphoblastic Leukaemia • Myeloblasts (10%) • Lymphoblasts (90%) - T or B • nuTdt+ / CD34+ • B-lineage: CD19+ / cyCD79a- / CD22- / 10+ • T-lineage: cyCD3- / CD7+

• Does AML originate from a HSC or does it arise from a more mature (non-HSC) progenitor and aberrantly acquire self-renewal properties?

Are AML aberrant HSC? • majority are CD34+/90- blasts ‣ Holden. BLOOD 1995; 86:60 • variably repopulate irradiated NOD/SCID mouse ‣ most are not stem cells

Bonnet. Nat Med 1997: 3: 730 • LSC within the CD34+/38- fraction • Re-populating cells within fractions: • CD34++/38-; CD34++/71-; CD34++/HLADR- ‣ Blair. BLOOD 1998; 92: 4325

• At diff disease stages, isolated proportions of: • Haem Stem Cells (HSC) • Common Myeloid Progenitors (CMP) • Granulocyte/Macrophage Precursors (GMP) • Megakaryocyte/Erythrocyte Precursors (MEP) • compared bcr-abl transcript levels in diff populations

HSC numbers not sig higher as disease progresses

More MEP at Chronic Phase; More GMP at Blast Crisis

Increased b -catenin expression in progenitors, not HSC

• Conclusion: • CML blasts are GMP cells, not HSC or MPP cells • Blasts acquire stem cell (self-renewal) properties via activation of wnt /b- catenin pathway

PNAS 2000; 97:7521 • paradox: some pt have persistent low level t(8;21)+ yet w long-term remission • ? t(8;21) PCR+ ≠ MRD • isolated diff populations from pt in CR & checked for t(8;21) by PCR

• Results: • at presentation: ‣ leuk cells are CD34+/38+/90-; ‣ PCR+ also in some B-cells but not T-cells; also in some CFU- E, CFU-mega, CFU-GM • at CR: ‣ PCR+ in some stem cells (CD34+/38-/90+), mono & B-cells; also in some CFU-E, CFU-mega, CFU-GM • Conclusion: • t(8;21) mutation occur at totipotent cell but in itself, is insuff to result in leukaemia • additional downstream mutations required for persistent proliferation & self-renewal (Leukaemia) ‣ LSC is downstream of totipotent HSC

Leukaemic cell of origin CML CML - BC Orkin, Cell 2008; 132:631

Rossi, Cell 2008; 132:681

Significance ? of LSC • More aggressive disease • Good risk AML have lower LSC numbers ‣ Ailles. BLOOD 1999; 94:1761 • MRD indicator • if LSC phenotype is different from normal progenitors • Potential therapeutic target

Search for LSC specific markers important

PNAS 2007; 104:11008 • search for LSC-specific surface markers in t(8;21) • made cDNA from stem-cell enriched fraction • screened for genes with surface expression using modified Signal Sequence Trap - Retroviral Expression (SST-REX) PCR • underlying aim: • for development of LSC-targetted Rx

• Results: • 35 candidate genes isolated • Expression levels of each candidate gene were compared in t(8;21) vs Normal BM CD34+/38- cells ‣ CD96 only gene w high expression in leuk over normal HSC

• Results in diff types of AML:

• Results of transplantation into irradiated mice: • CD96+ cells engraft recipients

• Conclusion: • Leuk SC phenotype CD34+/38-/90-/96+ ‣ this phenotype in normal person is not self-renewing ‣ phenotype similar in t(8;21)+ & t(8;21)- patients • differ from norm HSC CD34+/38-/90+/96- • CD96 possibly not a good therapeutic target ‣ CD96+ in T, NK-cells, kidney tubules, gut mucosa, vascular endothelium

Cell 2009; 138: 271 Cell 2009; 138: 286

Majeti. Cell 2009: 138: 286 • CD47+ in all mouse AML cell lines • CD47+ in human AML cells • Differential expression of CD47 on Stem cells ‣ CD47hi in AML LSC but CD47lo in norm HSC • CD47 expression inhibits phagocytosis

Rossi, Cell 2008; 132:681

Majeti. Cell 2009: 138: 286 • CD47 a/w poor outcome • CD47 a/w FLT3 ITD; ‣ t(8;21) mostly CD47-

LSC candidate markers Marker Function • CD123 unknown • CD44 homes to HSC niche • CLL-1 unknown • CD96 unknown • CD47 inhibits phagocytosis

Targetted anti-LSC Rx

Majeti. Cell 2009: 138: 286 • anti-CD47 depletes AML but spares normal HSC • (transplanted into NOD/SCID mice)

Nature Medicine. 2006:12 1167 • (transplanted in NOD/SCID mice)

Cell Stem Cell. 2009; 5: 31 • (transplanted in NOD/SCID mice)

Remarks: • Clinical impetus for detection and characterisation of early CD34+ subsets • LSC detection • earliest upstream progenitor w aberrant phenotype • more reflective of MRD status than the ‘downstream’ blast count • targetting Rx at LSC promising • in-vivo chemo / ex-vivo purging pre-auto SCT

CD34 subsets CD34 subsets 6% 9% 22% 62% 2% 2% 38% 57% Case #1 Case #2 total CD34+ 0.7% total CD34+ 0.6%

Immunophenotyping today • 8 Colour cytometers • interactions and artefacts are compounded • analysis more complex • Newer approaches to analysis / visualisation of results • Remove some of the subjectivity from the analysis

Data Visualisation Approaches Reference Images Live statistical input Summary Display