White Myeloid Cells

The myeloid lineage produces a diverse group of blood cells (leukocytes) involved in the defense of the body against foreign substances or infectious agents. Monocytes, neutrophils, eosinophils, basophils, and mast cells all arise from the common myeloid progenitor (CMP), which develops from bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow stem cells. However, leukocytes have different functions. Neutrophils kill invading bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology: Overview and fungi Fungi Fungi belong to the eukaryote domain and, like plants, have cell walls and vacuoles, exhibit cytoplasmic streaming, and are immobile. Almost all fungi, however, have cell walls composed of chitin and not cellulose. Fungi do not carry out photosynthesis but obtain their substrates for metabolism as saprophytes (obtain their food from dead matter). Mycosis is an infection caused by fungi. Mycology: Overview, eosinophils increase in parasitic infections, basophils and mast cells are key to allergic response as sources of histamine, and monocytes are released from bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow to become macrophages in the tissues. The development in the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow is regulated by different cytokines.

Last update:

Table of Contents

Share this concept:

Share on facebook
Share on twitter
Share on linkedin
Share on reddit
Share on email
Share on whatsapp

Overview

Definition

White myeloid cells are leukocytes developed from the common myeloid progenitor (CMP), which is derived from hematopoietic stem cells (HSCs) of the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow.

  • Not all leukocytes (WBCs) are derived from the myeloid progenitor.
  • 2 major groups of leukocytes:
    • Granulocytes (derived from the myeloid progenitor):
      • Basophils
      • Eosinophils
      • Neutrophils
      • Mast cells
    • Agranulocytes (derived from myeloid and lymphoid progenitors):
      • Monocytes (myeloid)
      • Lymphocytes Lymphocytes Lymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone marrow, starting from hematopoietic stem cells (HSCs) and progressing to common lymphoid progenitors (CLPs). B and T lymphocytes and natural killer (NK) cells arise from the lineage. Lymphocytes (lymphoid)

Cell description

Table: Cell description of agranulocytes
Type Nucleus Granules Characteristics and functions
Monocyte (3%–7% of differential count) Kidney shaped (indented or C shaped) None Characteristics:
  • Lifespan: hours to days
  • Largest leukocyte

Functions:
  • Differentiate into populations of tissue macrophages (including dendritic cells and osteoclasts)
  • All cells derived from monocytes are antigen-presenting cells.
  • Search for microbial cells and mount an immune response
Table: Cell description of granulocytes
Type Nucleus Granules Characteristics and functions
Neutrophil (50%–70% of differential count) Multilobed (3–5 lobes)
  • Fine
  • Faintly pink
Lifespan:
  • Approximately 6 hours (circulating)
  • Days (in tissues)

Target and function:
  • Kill and phagocytose bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology: Overview
  • Destruct fungi Fungi Fungi belong to the eukaryote domain and, like plants, have cell walls and vacuoles, exhibit cytoplasmic streaming, and are immobile. Almost all fungi, however, have cell walls composed of chitin and not cellulose. Fungi do not carry out photosynthesis but obtain their substrates for metabolism as saprophytes (obtain their food from dead matter). Mycosis is an infection caused by fungi. Mycology: Overview, restrict the growth of larger fungi Fungi Fungi belong to the eukaryote domain and, like plants, have cell walls and vacuoles, exhibit cytoplasmic streaming, and are immobile. Almost all fungi, however, have cell walls composed of chitin and not cellulose. Fungi do not carry out photosynthesis but obtain their substrates for metabolism as saprophytes (obtain their food from dead matter). Mycosis is an infection caused by fungi. Mycology: Overview
Eosinophil (1%–3% of differential count) Bilobed
  • Large
  • Dark pink
Lifespan:
  • Approximately 6 hours (circulating)
  • Days (in tissues)

Target and function:
  • Kill parasites and helminths
  • Immune response to allergic reactions
Basophil (0.5%–1% of differential count) Bilobed or trilobed
  • Large
  • Dark blue
Lifespan:
  • Hours to days

Target and function:
  • Modulation of the inflammatory response by histamine secretion
  • Surface receptors for IgE
  • Supplements actions of mast cells
Mast cell Round (margins obscured by packed granules) Purple to red
  • Granules rich in histamine and heparin
  • Found in tissues, but not in blood
  • Modulation of the type 1 hypersensitivity reaction through IgE receptors

Myelopoiesis

Myeloid cell production

  • Hematopoiesis:
    • 1st to 2nd month in utero: mesoderm of the yolk sac
    • By the 2nd month: moves to the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver (and spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen)
    • By the 5th month: occurs in the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow, which becomes the predominant source of blood cells
  • Myelopoiesis starts with multipotent HSCs in the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow.
  •  HSCs → multipotent progenitor (MPP) cells → CMP (which eventually differentiates into granulocytes, monocytes, platelets Platelets Platelets are small cell fragments involved in hemostasis. Thrombopoiesis takes place primarily in the bone marrow through a series of cell differentiation and is influenced by several cytokines. Platelets are formed after fragmentation of the megakaryocyte cytoplasm. Platelets, and erythrocytes Erythrocytes Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes)
Bone marrow hematopoiesis

Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones marrow hematopoiesis: proliferation and differentiation of the formed elements of blood.
IL-3: interleukin-3
CFU-GEMM: colony-forming unit–granulocyte, erythrocyte, monocyte, megakaryocyte
IL-2: interleukin-2
IL-6: interleukin-6
CFU-GM: colony-forming unit–granulocyte-macrophage
GM-CSF: granulocyte-macrophage colony-stimulating factor
M-CSF: macrophage colony-stimulating factor
G-CSF: granulocyte colony-stimulating factor
IL-5: interleukin-5
NK: natural killer
TPO: thrombopoietin
EPO: erythropoietin

Image by Lecturio. License: CC BY-NC-SA 4.0

Regulation

Table: Comparison of cytokines/growth factors
Cytokines/growth factors Activities Source
Stem cell factor (SCF) Stimulates all hematopoietic progenitor cells Bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones marrow stromal cells
Granulocyte-macrophage colony-stimulating factor (GM-CSF) Stimulates myeloid progenitor cells Endothelial cells, T cells T cells T cells, also called T lymphocytes, are important components of the adaptive immune system. Production starts from the hematopoietic stem cells in the bone marrow, from which T-cell progenitor cells arise. These cells migrate to the thymus for further maturation. T Cells
Granulocyte colony-stimulating factor (G-CSF) Stimulates neutrophil precursor cells Endothelial cells, macrophages
Monocyte colony-stimulating factor (M-CSF) Stimulates monocyte precursor cells Endothelial cells, macrophages
Interleukin-1 (IL-1) Regulation of cytokine secretion of many leukocytes Macrophages, T helper cells
Interleukin-3 (IL-3) Mitogen for all granulocyte and megakaryocyte/erythrocyte progenitor cells T helper cells
Interleukin-4 (IL-4) Development of basophils and mast cells, and activation of B-lymphocyte T helper cells
Interleukin-5 (IL-5) Development and activation of eosinophils T helper cells

Development

Neutrophils, eosinophils, basophils

  • Neutrophils are derived from the colony-forming unit granulocyte-macrophage (CFU-GM).
  • Eosinophils (Eo) and basophils (Ba) come from progenitor-cell CFU-Eo and CFU-Ba, respectively.
  • Subsequent stages:
    1. Myeloblast: 
      • 1st granulocytic precursor
      • Cytoplasm with no granules
      • Large nucleus and faint nucleoli
    2. Promyelocyte:
      • Azurophilic granules form.
      • The granules contain lysosomal hydrolases and myeloperoxidase.
    3. Myelocyte: 
      • 1st sign of differentiation: Specific granules develop for the particular cell type.
      • Different sets of genes are activated; lineages for the 3 types of granulocytes form.
      • Cell division ceases.
    4. Metamyelocyte: 
      • Granules are dispersed.
      • Nuclear indentation and lobulation occur.
      • Neutrophilic, basophilic, and eosinophilic metamyelocytes undergo further condensation of their nuclei.
  • Differentiation:
    • Neutrophils:
      • From the neutrophilic-metamyelocyte stage, neutrophils become band neutrophils or stab cells (intermediate stage with an elongated, not polymorphic, nucleus)
      • Segmented neutrophil: nearly mature
      • Mature neutrophil: exits to the peripheral blood
    • Eosinophils: from eosinophilic metamyelocyte → mature eosinophil
    • Basophils: from basophilic metamyelocyte → mature basophil
Granulopoiesis

Granulopoiesis: Images depict the stages of granulocyte development.
In the most immature stage, the myeloblast is characterized by a large nucleus with faint nucleoli and a nongranular, basophilic cytoplasm.
During the promyelocyte stage, the cell enlarges and azurophilic granules appear in the cytoplasm.
In the myelocyte stage, cell division ceases and specific granules appear in the cytoplasm.
During the metamyelocyte stage, the size of the cell decreases and nuclear morphology changes; the nucleus begins to indent. For neutrophils, the nucleus forms a horseshoe shape as a band cell and is multilobulated in the mature neutrophil.
For eosinophils, the nucleus becomes bilobed and the cytoplasm has eosinophilic granules.
For basophils, the nucleus is bilobed and the cell has basic granules.

Image by Lecturio. License: CC BY-NC-SA 4.0

Monocytes

  • Derived from the CFU-GM (similar to neutrophils)
  • Stages:
    • Monoblast: 
      • 1st monocyte precursor
      • Round nucleus
    • Promonocyte:
      • Convoluted, indented nucleus
      • Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables basophilic granules
    • Monocyte: 
      • Lobulated, indented nucleus
      • Occasional or no granules
      • Once recruited into tissues, the cell differentiates into macrophages.
Development of monocyte

Monocyte development starts from hematopoietic stem cells (HSCs) and progresses through stages to the colony-forming unit granulocyte-macrophage (CFU-GM):
The 1st monocyte precursor is the monoblast, which has a round or oval nucleus.
The promonocyte follows and has a convoluted nucleus.
The monocyte arises with an indented nucleus and is released from the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow to become a macrophage in the tissues.

Image by Lecturio. License: CC BY-NC-SA 4.0

Mast cells

  • Mast cells arise from the bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow: HSCs → CMP → CFU-GM → mast cell progenitor
  • Unlike other HSC-derived cells, mast cell progenitors (immature form) are released into the blood.
  • Mast cell progenitors are recruited to mucosal and epithelial tissues, undergo terminal differentiation, and become mature mast cells.

Clinical Relevance

  • Acute myeloid leukemia Acute Myeloid Leukemia Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the uncontrolled proliferation of myeloid precursor cells. Seen predominantly in older adults, AML includes an accumulation of myeloblasts and a replacement of normal marrow by malignant cells, which leads to impaired hematopoiesis. Acute Myeloid Leukemia ( AML AML Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the uncontrolled proliferation of myeloid precursor cells. Seen predominantly in older adults, AML includes an accumulation of myeloblasts and a replacement of normal marrow by malignant cells, which leads to impaired hematopoiesis. Acute Myeloid Leukemia): characterized by uncontrolled proliferation of myeloid precursor cells. Acute myeloid leukemia Acute Myeloid Leukemia Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the uncontrolled proliferation of myeloid precursor cells. Seen predominantly in older adults, AML includes an accumulation of myeloblasts and a replacement of normal marrow by malignant cells, which leads to impaired hematopoiesis. Acute Myeloid Leukemia includes an accumulation of myeloblasts. Normal marrow is replaced by malignant cells, which leads to impaired hematopoiesis. A clinical presentation consisting of fatigue, bleeding, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and infection is related to anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview, thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia, and lack of functional WBCs. Diagnosis is via peripheral blood smear and bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow biopsy showing myeloblasts. The precursor cells contain Auer rods. 
  • Chronic myeloid leukemia Chronic myeloid leukemia Chronic myeloid leukemia is a malignant proliferation of the granulocytic cell line characterized by a fairly normal differentiation. The underlying genetic abnormality is the Philadelphia chromosome, an abbreviated chromosome 22, resulting from reciprocal (9;22)(q34;q11) translocation. Chronic Myeloid Leukemia ( CML CML Chronic myeloid leukemia is a malignant proliferation of the granulocytic cell line characterized by a fairly normal differentiation. The underlying genetic abnormality is the Philadelphia chromosome, an abbreviated chromosome 22, resulting from reciprocal (9;22)(q34;q11) translocation. Chronic Myeloid Leukemia): malignant proliferation of the granulocytic cell line, with a fairly normal differentiation. The underlying genetic abnormality is the Philadelphia chromosome, an abbreviated chromosome 22 resulting from reciprocal (9;22)(q34;q11) translocation. Patients can be asymptomatic, or have sternal pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain and splenomegaly Splenomegaly Splenomegaly is pathologic enlargement of the spleen that is attributable to numerous causes, including infections, hemoglobinopathies, infiltrative processes, and outflow obstruction of the portal vein. Splenomegaly. Laboratory studies show elevated WBC with increased immature cells. Philadelphia chromosome demonstration by cytogenetic techniques is considered the gold standard of diagnostic testing. 
  • Chronic eosinophilic leukemia Chronic eosinophilic leukemia Chronic eosinophilic leukemia (CEL) is a chronic myeloproliferative neoplasm caused by autonomous clonal proliferation of normal-appearing eosinophils, resulting in increased eosinophils in the peripheral blood and bone marrow. The disorder is a myeloid variant of hypereosinophilic syndrome (HES) and is associated with tissue infiltration leading to end-organ damage. Chronic Eosinophilic Leukemia ( CEL CEL Chronic eosinophilic leukemia (CEL) is a chronic myeloproliferative neoplasm caused by autonomous clonal proliferation of normal-appearing eosinophils, resulting in increased eosinophils in the peripheral blood and bone marrow. The disorder is a myeloid variant of hypereosinophilic syndrome (HES) and is associated with tissue infiltration leading to end-organ damage. Chronic Eosinophilic Leukemia): a chronic myeloproliferative neoplasm caused by autonomous clonal proliferation of normal-appearing eosinophils, resulting in elevated eosinophils in the peripheral blood and bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow. The disorder is a myeloid variant of hypereosinophilic syndrome (HES) and associated with tissue infiltration, which leads to end-organ damage. Studies show an absolute eosinophilic count of ≥ 1.5 x 10⁹/L and bone marrow Bone marrow Bone marrow, the primary site of hematopoiesis, is found in the cavities of cancellous bones and the medullary canals of long bones. There are 2 types: red marrow (hematopoietic with abundant blood cells) and yellow marrow (predominantly filled with adipocytes). Composition of Bone Marrow blasts of 5%–19%. Evidence of clonal abnormality or elevated blasts is needed for diagnosis. Without either, idiopathic HES is the appropriate term. 
  • Mastocytosis: a group of disorders with excessive accumulation of mast cells in the tissue. Cutaneous mastocytosis is limited to the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin. Systemic mastocytosis infiltrates multiple organs outside the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin. KIT mutations are a major contributing factor. Symptoms include flushing, pruritus, and chronic allergic reactions.

References

  1. Dahlin, J., Hallgren, J. (2015). Mast cell progenitors: Origin, development and migration to tissues. Molecular Immunology, Volume 63, Issue 1, Pages 9–17. https://doi.org/10.1016/j.molimm.2014.01.018.
  2. Espinoza, V.E., Emmady, P.D. (2021). Histology, Monocytes. StatPearls. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557618/
  3. Kuijpers T. (2021). Structure and composition of neutrophils, eosinophils, and basophils. Kaushansky K, & Prchal J.T., & Burns Burns A burn is a type of injury to the skin and deeper tissues caused by exposure to heat, electricity, chemicals, friction, or radiation. Burns are classified according to their depth as superficial (1st-degree), partial-thickness (2nd-degree), full-thickness (3rd-degree), and 4th-degree burns. Burns L.J., & Lichtman M.A., & Levi M, & Linch D.C. (Eds.), Williams Hematology, 10e. McGraw Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=2962&sectionid=252530906
  4. Mescher A.L. (Ed.). (2021). Blood. Junqueira’s Basic Histology Text and Atlas, 16e. McGraw Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=3047&sectionid=255121436

Learn even more with Lecturio:

Complement your med school studies with Lecturio’s all-in-one study companion, delivered with evidence-based learning strategies.

Study on the Go

Lecturio Medical complements your studies with evidence-based learning strategies, video lectures, quiz questions, and more – all combined in one easy-to-use resource.

¡Hola!

Esta página está disponible en Español.

🍪 Lecturio is using cookies to improve your user experience. By continuing use of our service you agree upon our Data Privacy Statement.

Details