Barrett W. Dick, M.D. Director, Hematology Laboratories Memorial Medical Center Springfield. IL...
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Transcript of Barrett W. Dick, M.D. Director, Hematology Laboratories Memorial Medical Center Springfield. IL...
LEUKOPOIESISNORMAL AND ABNORMAL
Barrett W. Dick, M.D.Director, Hematology Laboratories
Memorial Medical CenterSpringfield. IL
Clinical Professor, Pathology and Medicine
Southern Illinois School of Medicine
June, 2000
Evolution of White Cells
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
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.
Granulopoiesis
Myeloblast
Promyelocyte
Neutrophil Myelocyte
Neutrophil Metamyelocyte
Neutrophil band form - "band"
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.
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.
Lymphocyte Transformation
Small Lymphocyte
Transformed lymphocytes aka:"Reactive", "Large", "Variant" or "Atypical"
Blood Smear Examination
Performance of a White Cell Differential
Smear Examination
Thin Area
Feather Edge
Performance of a White Cell Differential - General Principles
• Scan at low power:o Identify appropriate thin areao Evaluate quality of smear
• High power oil- 50X or 100X:o Scan for abnormal cells and make a qualitative
assessmento Perform 200 cell differentialo Rescan to confirm that differential is an accurate
representation
Confidence Interval for Manual Differentials
• On a 1-200 cell manual differential, if a cell type is reported as:o "50%", the 95% C.I. is ~40% - 60% .o ‘1%’, the C.I. is ~0-8% .
• A statistically meaningful differential - 1000 cell differential required but not practical
• Conclusions:o Scanning the smear for abnormalities is more
important than the diffo Absolute counts from the machine are more accurate
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
o Agranuloctosis/neutropenia- Monocytosis frequently
predicts bone marrow recovery
o Relative or absolute monocytosis is a frequent finding
in myelodysplastic syndromes
Absolute Counts Define Cytoses or Cytopenias
Wbc Normal Ranges (cells/cumm)
• Neutrophils: 1500-6500 (Caucasians)
800-1200 (African subpopulation
• Lymphocytes: 1500-3000
• Monocytes: <1000
• Eosinophils: <700
• Basophils: <200
• Seg/Band Ratio: 5-6:1
• Relative Monocytes: <10%
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
Normal Wbc Found in Peripheral Blood
Segmented Neutrophil
Neutrophil Segmented Form
Eosinophil
Basophil
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
Small Lymphocyte
Large Transformed Lymphocyte
In a normal blood smear, 15-17% of the lymphocytes may be large lymphocytes.
Large Granular Lymphocyte
Frequently, but arbitrarily included as reactive lymphocytes. The granules identify them as "killer" cells.,
Large granular lymphocytes- "LGL’s"
• There are at least two distinct subclasses of killer cells
o ADCC: antibody dependent cytotoxic cells; a subclass of CD8 cells. Require the presence of an antibody to be functional
o Natural killer cells: do not require the presence of an antibody
Monocyte
Monocyte
Reactive Lymphocyte Vs. Monocyte
• Bluish cytoplasm • Granules few and
larger • Indistinct
chromatin, more intensely stained
• Muddy blue-gray cytoplasm
• Many small azurophilic granules, barely visible
• "Ropy" chromatin
Variations in Normal Wbc
Neutrophil with Toxic Granules
Neutrophil band with Toxic Granules
Neutrophil with Dohle Body
Dohle Bodies are condensations of cytoplasmic RNA, stain blue-gray, and have the same significance as toxic granulation.
Neutrophil with Dohle Body
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.
Hypersegmented Neutrophil in Megaloblastic Anemia
Transformed lymphocytes aka:"Reactive", "Large", "Variant" or
"Atypical"
Abnormal WBC
Myeloblasts, Auer Rod
Lymphoblasts, Acute Lymphocytic Leukemia
Lymphoblasts are usually smaller than myeloblasts and frequently have little or no visible cytoplasm.
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.
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.
Pseudo Pelger-Huet Anomaly
Cells that look metamyelocytes are almost never found in the hereditary form.
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.
Sezary's Syndrome Cutaneous T-cell Lymphoma
The "cerebriform" nucleus is characteristic of some T cellleukemia/lymphomas
Hairy Cell Leukemia
Infectious Organisms
Intracellular organisms in HIV patients, Histoplasma on the left,suspected Cryptosporidium on right.