White Blood Cells: (Leukocytes)
Granulocytes: (Contain granules)
-Neutrophils (Fight bacteria; Phagocytic; Present in 1st Immune Response)
-Band (Immature)
-Polymorphonuclear (PMN) (Mature)
-Eosinophils (Fight parasites and found during allergic reactions)
-Basophils (Found during allergic reactions)
Agranulocytes: (No granules present)
-Monocytes (Immature; Mature into Macrophages)
-Macrophages (Mature Phagocytic Cells; Part of 1st Immune Response)
-Lymphocytes (Antibodies)
-T-Cells (T-lymphocytes) (Helper cells; Activate B-Cells to secrete antibodies)
-B-Cells (B-lymphocytes)
-Plasma Cells (Antibody-secreting)
-Natural Killer (NK) Cells (Directly attack viruses, virus-infected cells, cancer cells and cancer-infected cells)
White Blood Cell Development: Granulocytes (Neutrophils, Eosinophils and Basophils)
Myeloblast:
- Unipotent stem cell
- Large, 15-20 micrometers in size
- Will differentiate into a granulocyte
- It is found in the bone marrow and is the most immature cell in the myeloid series
- Matures in response to special signals
- Cytoplasm shows moderate basophilia and no granules or rare, delicate granules, or numerous azurophilic granules
- In pathologic conditions, sometimes Auer rods will be present
- In pathologic conditions, sometimes Auer rods will be present
- Large, oval-shaped nucleus
- Fine chromatin (reticulated)
- Nucleus is typically round, but may cleft or fold particularly if a pathologic condition exists
- 2-5 nucleoli (smaller circular areas in the middle of the nucleus containing rRNA)
- No granules yet
- N/C Ratio: 4:1
- Reference:
- Bone Marrow: 0-1% (make up <3% of the nucleated cells)
- Peripheral Blood: 0%
- If found in the peripheral blood, this may signify an acute non-lymphoid leukemia or a chronic myeloproliferative or myelodysplastic condition, such as myelodysplastic syndrome
- If found in the peripheral blood, this may signify an acute non-lymphoid leukemia or a chronic myeloproliferative or myelodysplastic condition, such as myelodysplastic syndrome
- Bone Marrow: 0-1% (make up <3% of the nucleated cells)
Auer Rod/Auer Body:
- Auer rods or Auer bodies are basically a clumping of granules
- About 1/3rd of acute myelogenous leukemias have cells containing Auer rods
- These rod-shaped, round or reddish rods found in the cytoplasm
- May be seen in approximately 1-10% of leukemic blast cells or immature granulocytes or monocytes
- When seen, this is typically diagnostic of an acute non-lymphocytic leukemia
- Promyelocytes may contain more than one Auer rod in a bundle in a leukemic state
Promyelocyte:
- Presence of granules appears at this stage, and they are red-to-purple and few in number (primary only, no secondary)
- Granulocyte precursors found in the bone marrow
- Cytoplasm is basophilic and the clear area of the promyelocyte represents the "HOF"
- Account for about 10% of nucleated cells in the normal bone marrow
- Nucleus is round-to-oval
- There are 1-3 nucleoli
- Chromatin is slightly coarser than that of the myeloblast
- Cell Size is 14-20 micrometers
- N/C Ratio: 3:1
- Reference:
- Bone Marrow: 2-5%
- Peripheral Blood: 0%
- Bone Marrow: 2-5%
Myelocyte
- Found in the bone marrow
- Cell size: 12-18 micrometers
- Nucleus is round-to-oval and may have one flattened side near the Golgi body, but no indentation
- Nucleoli are typically not visible
- Peroxidase-positive granules found in neutrophilic and eosinophilic myelocytes
- Few-to-moderate primary
- Variable number of secondary
- As the cell matures, the secondary granules differentiate the cell lineage
- Neutrophils
- Eosinophils
- Basophils
- As the cell matures, the secondary granules differentiate the cell lineage
- Coarse chromatin and more condensed than that of the promyelocyte
- Nucleus somewhat occluded by the presence of granules
- Cytoplasm is slightly basophilic
- N/C Ratio: 2:1
- Reference:
- Bone Marrow: 5-19%
- Peripheral Blood: 0%
Metamyelocyte
- Undergoing granulopoiesis
- Account for about 15-20% of nucleated cells in the bone marrow
- Starting to become a band cell
- Nucleus becomes indented like a kidney bean (indentation is <50% the diameter of the nucleus)
- Nucleoli are not visible
- Chromatin is clumped and is coarse
- Cytoplasm stains pale blue to pink
- There are few primary granules and many secondary granules
- N/C Ratio: 1.5:1
- Cell size ranges from 10-15 micrometers
- Reference:
- Bone Marrow: 13-22%
- Peripheral Blood: 0%
Band Cells
- There are 3 types of band cells: neutrophilic, eosinophilic and basophilic
- Cell size ranges from 10-15 micrometers
- Account for 5-10% of the nucleated cells in the bone marrow
- Curved nucleus is shaped like a band and is constricted, however, there is no threadlike filament
- Nucleoli are not visible
- The chromatin is coarse and clumped
- The cytoplasm stains pale blue to pink
- There are few primary granules and abundant secondary granules
- In the N/C ratio, the cytoplasm predominates
- If there is an increase in band neutrophils, this typically means that the bone marrow is producing more white blood cells and is responding to a signal to do so. This is referred to as "left shift", and will occur during infection or inflammation somewhere in the body
- A normal range of these in the peripheral bloodstream of adults ranges from 3-5%. Any rise in this number is referred to as bandemia (infections, sepsis, appendicitis)
- Reference:
- Bone Marrow: 17-33%
- Peripheral Blood: 0-5%
Neutrophils (Band):
A band neutrophil seen in the peripheral bloodstream is normal in the 3-5% range, but may signify infection or inflammation if seen in higher numbers.
- Cell size: 10-15 micrometers
- The nucleus has 2-5 lobes connected by thin filaments whose chromatin is not visible
- Chromatin is coarse and clumped
- The cytoplasm stains pale blue to pink
- There are rare primary granules and abundant secondary granules
- In the N/C ratio, cytoplasm predominates
- Reference:
- Bone Marrow: 3-11%
- Peripheral Blood: 50-70%
Neutrophils (PMN):
- Mature neutrophils
- Present in peripheral bloodstream
- The most prevalent of the 3 granulocyte types (40-75%)
- Most prevalent of ALL white blood cell types as well (50-70%)
- Low counts are referred to as neutropenia (certain infections, aplastic anemia, leukemia, medication, chemotherapy)
- Decreases in function are related to Diabetes mellitus and hyperglycemia (high blood sugar)
- Excesses are referred to as neutrophilia (bacterial infection, inflammation, burns, heart attack, medications like prednisone, steroids, epinephrine, cancers like chronic myelogenous leukemia, spleen removal, appendicitis)
- They don't live very long (only 4-90 hours)
- They are highly motile and move in response to chemical signals (chemotaxis)
- Normally contain 2-5 lobes
- Neutrophils with more lobes are referred to as hypersegmented, and this occurs in things like Vitamin B12 deficiency
- They are phagocytes that migrate towards the site of infection/inflammation
- Pus consists mostly of neutrophils, along with dead bacteria and cellular debris
- There are about 200 granules, which are dark blue-purple (azure)
- Release their granules by degranulation:
- Azurophilic granules (primary)
- Specific granules (secondary)
- Tertiary granules
- Azurophilic granules (primary)
Eosinophils:
Eosinophils are present when a person has a parasite infection, is on certain medications, or is having an allergic reaction to something or an asthma attack. They encompass about 1-6% of white blood cells.
Eosinopenia is a decrease in eosinophils (burns, acute infections, Cushing's syndrome, stress, or use of steroids), whereas eosinophilia is an increase in them, seen during an allergic reaction or parasite infection. Some types of lymphomas and leukemias are associated with this condition as well.
Eosinopenia is a decrease in eosinophils (burns, acute infections, Cushing's syndrome, stress, or use of steroids), whereas eosinophilia is an increase in them, seen during an allergic reaction or parasite infection. Some types of lymphomas and leukemias are associated with this condition as well.
- Cell size: 12-17 micrometers
- N/C Ratio: 2:1
- The nucleus has 2-3 lobes connected by thin filaments without visible chromatin
- Nucleoli are usually not visible
- The chromatin is coarse and more condensed
- The cytoplasm is colorless-to-pink with rare primary granules and abundant orange to red, round secondary granules and may have irregular borders
- N/C ratio: Cytoplasm predominates
- Reference:
- Bone Marrow: 0-3%
- Peripheral Blood: 0-5%
Charcot-Leyden Crystals:
- Charcot-Leyden crystals are associated with eosinophilia
- Causes include allergies, parasitic infection, a skin disorder, a malignancy, a leukemia, immunodeficiency disease, or drugs such as chemotherapy or human interleukin therapy
- Charcot-Leyden protein is a major protein that is part of the eosinophil, so a chronic eosinophilia, inflammatory condition, or an intense reaction can cause the formation of these crystals, which are shaped like hexagons or toothpicks
- Found in secretions, body fluids, or tissues
- Associated with conditions like asthma or allergies or parasitic infections or certain leukemias
- May be seen intracellularly inside macrophages
Basophils:
Basophils are rare and make up just 0.5-1% of white blood cells. They are the causative agent of the symptoms an individual experiences during an inflammatory response, during acute and chronic allergies, anaphylaxis, hay fever, asthma, seasonal allergies, and even atopic dermatitis. They release histamine, a granule responsible for a natural immune response, but results in itching (skin, mucous membranes), watery eyes, runny nose, swelling of the throat, gastrointestinal reactions like cramping and diarrhea, sneezing, itchy throat. They are also seen in parasite infections.
The large granules obscure the nucleus, making it difficult to see. Basopenia is a decrease in basophils, and basophilia is an increase in them. Basopenia is common in chronic itching. Basophilia is quite rare, but is associated with some types of leukemias and lymphomas.
The large granules obscure the nucleus, making it difficult to see. Basopenia is a decrease in basophils, and basophilia is an increase in them. Basopenia is common in chronic itching. Basophilia is quite rare, but is associated with some types of leukemias and lymphomas.
- Cell size: 10-14 micrometers
- The nucleus has 2 lobes connected by thin filaments without visible chromatin
- Nucleoli are not visible
- The chromatin is coarse and clumped
- The cytoplasm is lavender to colorless with rare primary granules and deep purple secondary granules
- Secondary granules are variable in number and unevenly distributed, and they typically obscure the nucleus
- Granules are water-soluble
- Granules may be washed out during the staining process, so they appear as empty areas
- N/C Ratio: Cytoplasm predominates
- Reference:
- Bone Marrow: <1%
- Peripheral Blood: 0-1%
White Blood Cell Development: Agranulocytes (Monocytes, Macrophages):
Monoblast:
Promonocyte
- The cell size is 12-20 micrometers
- The nucleus has an irregular shape to it and it is deeply indented
- The nucleoli may or may not be visible, and there are 2
- The chromatin is fine
- The cytoplasm stains blue-to-gray with fine azurophilic granules
- The N/C ratio is 2.0-3.1
- Reference:
- Bone Marrow: <1%
- Peripheral Blood: 0%
Monocyte
- The cell size is 12-20 micrometers (a bit larger than a neutrophil)
- The nucleus is variable and may be round, kidney-shaped, heart-shaped, horseshoe-shaped, and often has "brain-like" folds and convolusions
- The nucleoli are not visible
- The chromatin is lacy
- The cytoplasm stains blue-gray and may even have pseudopods and there are many fine granules that cause the cytoplasm to resemble "ground glass"
- There are absent to numerous vacuoles
- The N/C Ratio is variable
- Reference:
- Bone Marrow: 2%
- Peripheral Blood: 3-11%
Macrophage (Mature Phagocyte):
- The cell size is 15-80 micrometers
- The nucleus is eccentric and may be off-centered, egg-shaped, indented, elongated, or reniform
- There are 1-2 nucleoli which may or may not be visible
- The chromatin is fine and dispersed
- The cytoplasm is abundant and has irregular borders, and the cell may resemble a "fried egg"
- May contain ingested material, such as bacteria or cell debris
- Contains many coarse azurophilic granules
- Many vacuoles may be present
- Reference:
- N/A
Lymphocyte Development:
Lymphoblast
- Cell Size: 10-18 micrometers
- The nucleus is round-to-oval
- There are one or more nucleoli
- The chromatin is fine and evenly stained
- The cytoplasm is moderate to deeply basophilic with no granules
- The N/C Ratio is 4:1
- Reference:
- Bone Marrow: not defined
- Peripheral Blood: 0%
Prolymphocyte
Lymphocyte (B Lymphocyte or T Lymphocyte)
Lymphocytes are found in the lymph and lymph nodes of the immune system. They play a key role in cytotoxic, adaptive immunity, and some form long-term memory cells. T-lymphocytes, or T cells, play a key role in cell-mediated, cytotoxic adaptive immunity. They activate B-lymphocytes, or B cells, some of which secrete immunoglobins, or antibodies (plasma cells). This is referred to as humoral immunity, also adaptive immunity. Active immunity is triggered when we encounter viruses, bacteria, parasites, or other microbes that could make us ill, where they are actively secreted and fight off disease. Passive immunity occurs via antibodies being transferred from mother to infant during breast-feeding, and also when we receive immunizations containing small pieces (antigens, proteins, or sugars) of live or inactivated viruses or bacteria, which trigger the immune response and in turn help to create long-term memory cells.
Lymphocytes are recognized by their large nucleus in comparison to the cytoplasm of the cell. T-cells are synthesized in the thymus gland, whereas B-cells are synthesized in the bone marrow, lymph, and Peyer's Patches of the gut. Their main job is to recognize things that are foreign to the body and should not be there (non-self). They are able to distinguish "self" from "non-self" things. Sometimes, though, if this mechanism goes awry, this is the basis for autoimmune diseases and allergic or delayed allergic reactions, when the lymphocytes treat "self" tissues as "non-self" or foreign, resulting in attack of the body's own tissues. When organ transplants, skin grafts, blood transfusions, or bone marrow transplants are required, this is why they have to be matched so carefully because so many factors can trigger an allergic response.
When someone is immunocompromised, they are either missing or have lost some of their immunity or lymphocytes. HIV/AIDS, for example, attacks a specific type of T-lymphocyte (CD4+) responsible for activating plasma B-lymphocytes to secrete antibodies. Without either of these cells, the immune system is basically shot, and the individual becomes susceptible to just about anything in the atmosphere that could possibly make them sick. Some types of leukemias or lymphomas attack one or both of these types of lymphocytes.
Increases in lymphocytes typically mean an individual has a viral infection. Some lymphomas and leukemias cause this as well. Decreases in lymphocytes occur after surgery, after an accident or injury, HIV/AIDS, or things like SCID (Severe Combined Immune Deficiency).
Reactive lymphocytes are a sign of a viral infection such as Epstein-Barr Virus (infectious mononucleosis).
Lymphocytes are recognized by their large nucleus in comparison to the cytoplasm of the cell. T-cells are synthesized in the thymus gland, whereas B-cells are synthesized in the bone marrow, lymph, and Peyer's Patches of the gut. Their main job is to recognize things that are foreign to the body and should not be there (non-self). They are able to distinguish "self" from "non-self" things. Sometimes, though, if this mechanism goes awry, this is the basis for autoimmune diseases and allergic or delayed allergic reactions, when the lymphocytes treat "self" tissues as "non-self" or foreign, resulting in attack of the body's own tissues. When organ transplants, skin grafts, blood transfusions, or bone marrow transplants are required, this is why they have to be matched so carefully because so many factors can trigger an allergic response.
When someone is immunocompromised, they are either missing or have lost some of their immunity or lymphocytes. HIV/AIDS, for example, attacks a specific type of T-lymphocyte (CD4+) responsible for activating plasma B-lymphocytes to secrete antibodies. Without either of these cells, the immune system is basically shot, and the individual becomes susceptible to just about anything in the atmosphere that could possibly make them sick. Some types of leukemias or lymphomas attack one or both of these types of lymphocytes.
Increases in lymphocytes typically mean an individual has a viral infection. Some lymphomas and leukemias cause this as well. Decreases in lymphocytes occur after surgery, after an accident or injury, HIV/AIDS, or things like SCID (Severe Combined Immune Deficiency).
Reactive lymphocytes are a sign of a viral infection such as Epstein-Barr Virus (infectious mononucleosis).
- The Cell Size: 7-18 micrometers
- Nucleus is round-to-oval with a possible slight-indentation as seen below
- Nucleoli may or may not be present
- Chromatin is condensed to deeply condensed
- The cytoplasm is scant-t0-moderate
- Sky blue
- Vacuoles may be present
- Small lymphocytes: smaller amount of cytoplasm
- Large lymphocytes: larger amount of cytoplasm
- Few azurophilic granules
- N/C Ratio: 3.0-5:1
- Reference:
- Bone Marrow: 5-15%
- Peripheral Blood: 20-40%
Reactive Lymphocytes:
Natural Killer (NK) Cell:
Natural killer (NK) cells directly attack viruses, virus-infected cells, cancer, and cancer-infected cells. They secrete potent enzymes such as porforins that literally poke holes in the cell membrane, causing the ingredients to leak out and the cell to explode and die. They play a key role in cell-mediated cytotoxic (innate) immunity.
Plasma Cell:
- Cell Size; 8-20 micrometers
- Nucleus is round or oval and eccentric (off-centered)
- No nucleoli
- Coarse chromatin
- Cytoplasm is deeply basophilic with a perinuclear clear zone
- No granules
- No to several vacuoles
- N/C Ratio: 2.0-1:1
- Reference:
- Bone Marrow: 0-1%
- Peripheral Blood: 0%
Mast Cells:
- Cell size is 12-25 micrometers
- Nucleus is round-to-oval, located in the center, but may be obscured by granules
- Cytoplasm is lavender to colorless with many dark blue granules
- Reference:
- Bone marrow: <1%
- Peripheral Blood: 0%