MLAB Hematology Keri Brophy-Martinez Hematopoiesis

2 Process of blood cell production, development and replacement. Formation and development usually occurs in the bone marrow. Purpose Allows hematopoietic system to respond to stimuli such as infection, bleeding, or hypoxia by increasing production of cell line needed.

3

Hematopoietic Precursor Cells Stem Cells/ Pluripotential Progenitor CellsMaturing Cells 0.5% of total hematopoietic precursors 3% of total hematopoietic precursors >95% of total hematopoietic precursors Population size stablePopulation amplified by proliferation Not morphologically recognizable Morphologically recognizable Multilineage differentiationMultipotentialCommitted cells

Cell Growth Factors Cytokines Growth factors secreted by cells for the purpose of cell-to- cell communication They stimulate the pluripotential stem cells to proliferate and differentiate. GF’s must be present to “grow” hematopoietic precursor cells.

Cytokines Include interleukins, lymphokines, monokines, interferons, chemokines and colony stimulating factors Colony Stimulating Factors or CSF These regulate blood cell development. CSF’s are being synthetically manufactured to treat diseases. Examples  G-CSF: Stimulate granulocyte production, Used to treat cancer and AIDS patients with low WBC. Trade name is Neupogen  GM-CSF - Stimulate granulocyte-macrophage production, Used to treat cancer patients with low WBC. Trade name is Leukine.  EPO - Stimulate erythrocyte production, Used to treat chronic anemia caused by renal failure, increase RBC prior to surgery which may cause blood loss, illegally by athletes to boost performance. Trade name is Epogen or Procrit.

Review of Cell Morphology

Cell Morphology Cell Membrane Outer boundary of the cell Allows passage of nutrients, ions and information between cytoplasm and the exterior Location of surface markers Phospholipid bilayer

Cell Membrane: Phospholipid Bi-layer

Cellular Components Cytoplasm: Location of metabolic activities Golgi complex: involved in formation of gamma globulins, lysosomes, specific granules and other cellular components. Ribosomes: RNA, synthesize proteins Endoplasmic reticulum: Communication system with the nucleus, smooth or rough Mitochrondria: furnish cell with energy Lysosomes: granules with hydrolytic enzymes.

Cellular Components Nucleus: Chromatin Dark staining chromosomal material composed of DNA and proteins. DNA regulates all cellular functions Nucleolus/Nucleoli Pale staining patches rich in RNA, DNA Nuclear envelope Double membrane which surrounds the nuclear contents.

General Morphological Changes in Cell Maturation Basophilic cytoplasm to less basophilic Reduction in cell size Reduction in size of nucleus Condensation of nuclear chromatin

Term: Nuclear to Cytoplasmic Ratio N/C ratio: Ratio of the size of the nucleus of a cell to the size of the cytoplasm N/C ratio decreases with maturity as the nucleus decreases in size and the cytoplasm becomes more abundant Immature “blast” cell has a large nucleus, small amount of cytoplasm. N/C ratio is high

Lab Method: Wright’s Stain Stain used to identify cells on blood smear Eosin is acid stain - stains red Methylene is basic stain - stains shades of blue Staining red Staining blue

Cluster Designation (CD) Cluster Designation (CD) nomenclature Monoclonal antibodies specific to cell surface markers Allows for the phenotypic characterization of cells in disease states Applications Flow cytometry  Cells labeled with monoclonal antibodies are sorted and enumerated to identify specific populations of cells. Example CD4 and CD8 Markers for helper and cytotoxic T cells Monitor progress of HIV infection