MLT 251 - Hematopoiesis: Leukocytes OBJs

Familiarize yourself with more hematology concepts.

Describe each stage of maturation and explain their associated characteristics for the following cell lines:

a) Myelocytic

b) Lymphocytic

c) Monocytic

d) Plasmacytic

e) Megakaryocytic

The maturation stages for each cell line include the following:

a) Myelocytic: Includes stages from myeloblast to promyelocyte, myelocyte, metamyelocyte, and mature granulocyte, characterized by gradual changes in size, nuclear morphology, and granule appearance.

b) Lymphocytic: Involves lymphoblast, prolymphocyte, and lymphocyte stages, showing progressive differentiation with increasing chromatin density and cell surface markers.

c) Monocytic: Progresses from monoblast to promonocyte and finally to monocyte, marked by changes in cell size, cytoplasmic qualities, and nucleus shape.

d) Plasmacytic: Starts with plasmablasts and develops into plasma cells, identifiable by an eccentric nucleus and abundant basophilic cytoplasm due to immunoglobulin production.

e) Megakaryocytic: Maturation involves megakaryoblast and promegakaryocyte stages, culminating in megakaryocytes that are large with multilobed nuclei, involved in platelet production.

Explain the function of:

a) Neutrophils

b) Eosinophils

c) Basophils

d) Lymphocytes

e) Plasmacytes

f) Monocytes

g) Platelets

a) Neutrophils: Key players in the innate immune response, they phagocytize pathogens and release enzymes that fight infection.

b) Eosinophils: Primarily involved in combating parasitic infections and mediating allergic reactions through the release of inflammatory substances.

c) Basophils: Release histamine and other mediators of inflammation; play a role in the allergic response and help to defend against parasites.

d) Lymphocytes: Central to the adaptive immune response, they include T cells, B cells, and natural killer cells that target specific pathogens.

e) Plasmacytes: Fully differentiated B cells that produce antibodies to neutralize pathogens; crucial for the humoral immune response.

f) Monocytes: Differentiate into macrophages and dendritic cells upon entering tissues; they phagocytize pathogens and present antigens to activate T cells.

g) Platelets: Cell fragments essential for clotting; they aggregate at the site of vascular injury to help prevent blood loss.

Recognize, differentiate and identify each white blood cell lineage from the blast to the mature stage.

The process involves classifying and understanding the distinct morphological and functional characteristics of various leukocyte lineages, from early precursor (blast) forms through to their fully mature forms.

Recall the term used when reporting blasts of any cell line.

Blasts

Describe the morphology of early cells in the platelet lineage and recall which forms may be seen in the peripheral blood.

The morphology of early cells in the platelet lineage, such as megakaryoblasts and promegakaryocytes, includes a large size, abundant cytoplasm, and a lobulated nucleus. In peripheral blood, usually only platelets are seen, as these precursors remain in the bone marrow.

Recognize and identify WBC variations and inclusions.

State conditions associated with each of the WBC variations and inclusions.

Recognize the WBC type(s) in which each of the variations and inclusions discussed in this lesson may be observed.

List the terms and criteria used when reporting WBC and platelet morphology.

List the common artifacts that may be encountered while performing a white cell differential and RBC morphology.

Differentiate cells included in a differential from cells that are reported as number seen while performing the differential.

Explain the term platelet satellitism and describe how it may impact the platelet count.

Platelet satellitism is the phenomenon in which platelets cluster around white blood cells, often leading to falsely low platelet counts in automated blood analysis. This clustering can interfere with accurate platelet measurement and may require manual counting to confirm results.

Recall how to resolve platelet satellitism to obtain an accurate platelet count.

This refers to the phenomenon in which platelets adhere to leukocyte surfaces, which can falsely lower platelet counts in automated cell counters. Resolving this typically involves re-evaluating the sample with a manual count or using a different anticoagulant.

Recall the WBC type that may be reported as smudge cells.

Lymphocytes, particularly in chronic lymphocytic leukemia (CLL) of smudge cells.

Describe the method for reporting NRBCs and recall why this is necessary.

The method for reporting NRBCs includes counting them alongside leukocytes in the differential count and adjusting the white blood cell count accordingly. This is necessary to provide an accurate assessment of the actual leukocyte population, as NRBCs can falsely elevate the WBC count.