1. Leukopoiesis Normal and abnormal
Barrett W. Dick, M.D.
Director, Hematology Laboratories
Memorial Medical Center
Springfield. IL
Clinical Professor, Pathology and Medicine
 Southern Illinois School of Medicine
June, 2000

2. Evolution of White Cells

3. Stem cell vs. Progenitor Cell
Stem cell: a primitive cell that is capable of both self renewal and differentiation. Upon differentiation, it can develop into myeloid or lymphoid lineages.
 Progenitor cell: a primitive cell beyond the stem cell stage that is committed to lineage differentiation

4. Evidence for Separate Common Progenitor Cell for B Lymphocytes and Myeloid Progenitor
Philadelphia chromosome is found in CML and a significant fraction of ALL, common B cell type.
Blast crisis in CML is frequently lymphoblastic, almost always B cell type.

5. Granulopoiesis

6. Myeloblast

7. Promyelocyte

8. Neutrophil Myelocyte

9. Neutrophil Metamyelocyte

10. Neutrophil band form - "band"

11. Neutrophil segmented form - "seg"
To be considered a segmented form, there must be at least one point where the the nucleus is segmented into two lobes with the connection between the containing no visible DNA (1). If there is visible DNA (2), it is not considered a segment.

12. Neutrophil Maturation
When a differential count is performed, traditionally, the device used for tallying the cells is arranged with the least mature cells on the left. This is the historic origin of the term "shift to the left" describing a relative increase in immature forms.

13. Lymphocyte Transformation

14. Small Lymphocyte

15. Transformed lymphocytes aka: "Reactive", "Large", "Variant" or "Atypical"

16. Blood Smear Examination

17. Performance of a White Cell Differential

18. Smear Examination
Thin Area
Feather Edge

19. Performance of a White Cell Differential - General Principles
Scan at low power:
Identify appropriate thin area
Evaluate quality of smear
High power oil- 50X or 100X:
Scan for abnormal cells and make a qualitative assessment
Perform 200 cell differential
Rescan to confirm that differential is an accurate representation

20. Confidence Interval for Manual Differentials
On a cell manual differential, if a cell type is reported as:
"50%", the 95% C.I. is ~40% - 60% .
‘1%’, the C.I. is ~0-8% .
A statistically meaningful differential cell differential required but not practical
Conclusions:
Scanning the smear for abnormalities is more important than the diff
Absolute counts from the machine are more accurate

21. Exceptions to the Absolute Counts "Rule"
% Segs compared % Bands - Ratio of the two defines a "left shift"
% Mono’s - Relative monocytosis is important in some clinical situations
Agranuloctosis/neutropenia- Monocytosis frequently predicts bone marrow recovery
Relative or absolute monocytosis is a frequent finding in myelodysplastic syndromes

22. Absolute Counts Define Cytoses or Cytopenias

23. Wbc Normal Ranges (cells/cumm)
Neutrophils: (Caucasians)
(African subpopulation
Lymphocytes:
Monocytes: <1000
Eosinophils: <700
Basophils: <200
Seg/Band Ratio: 5-6:1
Relative Monocytes: <10%

24. Principles of Blood Smear Examination
A 200 cell differential is a semi-quantitative estimate of the actual diff because the sampling error is very high - you are looking at a very small sample of a very large population
When a differential is reported, what it should mean is that an experienced individual has examined that smear and, other than what was reported, no significant abnormalities were seen
In practice, because of forced cutbacks in staffing, this currently is unlikely to be the case in most institutions
Conclusion: You better learn to examine blood smears

25. Normal Wbc Found in Peripheral Blood

26. Segmented Neutrophil

27. Neutrophil Segmented Form

28. Eosinophil

29. Basophil

30. Basophil
Basophil granules are very soluble. In this example they are partially dissolved and are easily mistaken for toxic granules in a neutrophil. The background cytoplasm in a basophil is gray in contrast to the salmon-pink color in a neutrophil

31. Small Lymphocyte

32. Large Transformed Lymphocyte
In a normal blood smear, 15-17% of the lymphocytes may be large lymphocytes.

33. Large Granular Lymphocyte
Frequently, but arbitrarily included as reactive lymphocytes. The granules identify them as "killer" cells.,

34. Large granular lymphocytes- "LGL’s"
There are at least two distinct subclasses of killer cells
ADCC: antibody dependent cytotoxic cells; a subclass of CD8 cells. Require the presence of an antibody to be functional
Natural killer cells: do not require the presence of an antibody

35. Monocyte

36. Monocyte

37. Variations in Normal Wbc

38. Neutrophil with Toxic Granules

39. Neutrophil band with Toxic Granules

40. Neutrophil with Dohle Body
Dohle Bodies are condensations of cytoplasmic RNA, stain blue-gray, and have the same significance as toxic granulation.

41. Neutrophil with Dohle Body

42. Hypersegmented Neutrophil
Hypersegmented neutrophils are classically associated with megaloblastic processes. However, they are commonly present when there is a neutrophilia. Rarely, it is a hereditary abnormality.

43. Hypersegmented Neutrophil in Megaloblastic Anemia

44. Transformed lymphocytes aka: "Reactive", "Large", "Variant" or "Atypical"

45. Abnormal WBC

46. Myeloblasts, Auer Rod

47. Lymphoblasts, Acute Lymphocytic Leukemia
Lymphoblasts are usually smaller than myeloblasts and frequently have little or no visible cytoplasm.

48. Myelocyte - Eo/Baso?
Abnormal myelocyte frequently interpreted as having both eosinophil and basophil granules. Most likely this is a normal eosinophil myelocyte with primary granules. In either case the significance is they are virtually only seen in the blood in chronic myeloproliferative disorders.

49. Pelger-Huet Anomaly
The Pelger-Huet anomaly can be either hereditary or acquired. The main features are exaggerated nuclear clumping and hyposegmetation. The latter manifests itself as "increased " band counts.

50. Pseudo Pelger-Huet Anomaly
Cells that look metamyelocytes are almost never found in the hereditary form.

51. Hypogranular Neutrophils
The color of normal neutrophils is due to their granules. When they are poorly granulated they appear gray which is the normal cytoplasmic color.

52. Sezary's Syndrome Cutaneous T-cell Lymphoma
The "cerebriform" nucleus is characteristic of some T cellleukemia/lymphomas

53. Hairy Cell Leukemia

54. Infectious Organisms
Intracellular organisms in HIV patients, Histoplasma on the left,suspected Cryptosporidium on right.