Presentation on theme: "Barrett W. Dick, M.D. Director, Hematology Laboratories Memorial Medical Center Springfield. IL Clinical Professor, Pathology and Medicine Southern Illinois."— Presentation transcript:
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
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
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.
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.
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.
Thin AreaFeather Edge
Scan at low power: o Identify appropriate thin area o Evaluate quality of smear High power oil- 50X or 100X: o Scan for abnormal cells and make a qualitative assessment o Perform 200 cell differential o Rescan to confirm that differential is an accurate representation
On a 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 cell differential required but not practical Conclusions: o Scanning the smear for abnormalities is more important than the diff o Absolute counts from the machine are more accurate
% Segs compared % Bands - Ratio of the two defines a "left shift" % Monos - 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
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
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
In a normal blood smear, 15-17% of the lymphocytes may be large lymphocytes.
Frequently, but arbitrarily included as reactive lymphocytes. The granules identify them as "killer" cells.,
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
Dohle Bodies are condensations of cytoplasmic RNA, stain blue-gray, and have the same significance as toxic granulation.
Hypersegmented neutrophils are classically associated with megaloblastic processes. However, they are commonly present when there is a neutrophilia. Rarely, it is a hereditary abnormality.
Lymphoblasts are usually smaller than myeloblasts and frequently have little or no visible cytoplasm.
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.
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.
Cells that look metamyelocytes are almost never found in the hereditary form.
The color of normal neutrophils is due to their granules. When they are poorly granulated they appear gray which is the normal cytoplasmic color.
The "cerebriform" nucleus is characteristic of some T cellleukemia/lymphomas
Intracellular organisms in HIV patients, Histoplasma on the left,suspected Cryptosporidium on right.