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CP Unknown Heme-10/19/2011 Kumaran Mudaliar and Girish Venkataraman Loyola University Medical Center, Pathology.

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Presentation on theme: "CP Unknown Heme-10/19/2011 Kumaran Mudaliar and Girish Venkataraman Loyola University Medical Center, Pathology."— Presentation transcript:

1 CP Unknown Heme-10/19/2011 Kumaran Mudaliar and Girish Venkataraman Loyola University Medical Center, Pathology

2 What cells are the purple population? -Plasma cells What cells are these?- hematogones

3 Additional plot of same case

4 Explain the gates in this tube containing CD45, CD19, CD20, kappa and lambda Primary gate CD19/SSC Light chain negative cells colored green and forwarded to show on all plots.

5 Hematogones Hematogones: physiologic precursors of B-cells 70 years ago, distinct lymphoid appearing cells in the bone marrow (BM). Hematogones (hematogonia, meaning blood-maker) 662 patients – 8% pts had 5% or more of hematogones 24.6% < 16 YO had hematogones 6.3% > 16 YO had hematogones MC in patients: lymphoma, marrow regenerative states, immuno cytopenias, AIDS

6 Problem At 5% level, they are conspicuous on marrow smear and can be confused with neoplastic lymphoblasts

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10 Reference Ranges? No accepted reference ranges – BM examination is not performed in healthy people

11 3 stages of Hematogone Maturation Early – Usually comprise a small minority, but can become expanded in regenerating marrows – No expression of CD 20 /CD34+ Intermediate – Majority in most marrows – -CD34-/CD20 dim/CD10+ Late – In contrast to mature B cells, Cd34-/CD20+/maintain dim CD10. Light chain surface+

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17 Gated on all CD19+ cells Stage 1 Hematogones CD34+/CD10+ Stage 2 hematogones Dimmer CD10, CD20 het Stage 3 hematogones -bright CD20, dim CD10 >90% of B-cells in this case are hematogones Stg 2 (red) and stg 3 (blue) Hematogones lack CD34

18 Immunophenotype CD 10+ CD 19+ CD 20+ Variable expression CD 38+ CD 45+ TdT + [subset] CD 34 + [subset] Kappa & Lambda -

19 Differences between hematogones and lymphoblasts Both present in CD 45 dim gate Hematogones: low side scatter – Consistent, highly reproducible, maturational pattern – No aberrant or asynchronous antigen expression B-ALL: relatively higher side scatter – Phenotypic abnormalities: Myeloid Markers: 13, 33, 15 T-cell: 2, 5, 7 Concurrent expression: TdT and cytoplasmic IgM; 34 and 20 ; 34 and surface light chains Loss of antigen expression on blasts: 45 – ; 10 – [B-ALL with MLL abnlties] ; 34 – [E2A-PBX1 fusion]

20 Even tho both may express an antigen, difference in expression patterns and levels of specific antigens exist – IF TdT: hematogones (coarsely granular / speckled) to blasts (finely granular / even distribution) – Also, hematogones have higher #s of TdT and CD 10 molecules / cell Leads to brighter expression on FC – Hematogones have less CD 19 molecules/ cell Hence dimmer expression on FC

21 BM Core Biopsies Hematogones: dispersed throughout marrow Blasts: small clusters (> 5 cells)

22 Issues Differentiation can be challenging Left Shifted Hematogones – Early stages after BM transplantation Anti-CD20 immunotherapy – Majority of B-ALL lack CD20 expression. -Phenotypic change

23 Sources McKenna RW, et al. Immunophenotypic analysis of hematogones (B-lymphocyte precursors) in 662 consecutive bone marrow specimens by 4-color flow cytometry. Blood Oct 15;98(8):


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