• Morphological disorder of the RBC
• Changes in the morphology and color of erythrocytes include changes in
• shape,
• size
• inclusions in or on the erythrocyte.
• Color
• Each of these morphological abnormalities provides information about disease processes that may be present.
• Hypochromic red blood cells are pale and have increased central pallor (more pale)
Erythrocyte color Hypochromasia
• It is the result of decreased hemoglobin concentration from iron deficiency (iron deficiency anemia)
• The RBC cells number in the circulatory system may be normal
• but the RBC size become reduced
 Torocytes- bowl-shaped
 pale center and dark periphery with demarcation in between
 The concentration of the hemoglobin is normal in spite of the dark periphery
 Polychromasia/
(Polychromatophilia)
Erythrocyte
morphology (size
and shape)
 Young erythrocytes that have been released early.
 Usually, they are large and bluer (basophilic) in color than mature erythrocytes.
 The blue color results from organelles
 The presence or absence of polychromatophilic erythrocytes is very important when determining the
cause of anemia.
 Polychromasia detected If anemia is due to blood loss or blood destruction
 Except Horse: horse will not release polychromasia or /insignificant number/ of polychromasia
release
 No Polychromasia will be detected If the anemia is caused by erythroid hypoplasia or aplasia
within the marrow
Spherocytes
 small erythrocytes with no central pallor
 dark throughout the red cell (condensed cell)
 small sized and matured cell, lack concavity
 Spherocytes are formed when a macrophage removes an abnormal portion of the erythrocyte membrane,
causing the erythrocyte to form a sphere, instead of the normal biconcave disc (partial phagocytosis).
 During which the size of the RBC become decreased (compressed) that cause the disapperarance of the
pale area of the RBC. Thus spherocyte will appear small and dense.
 Spherocytes has normal Hgb concentration
 It is a hallmark of immune-mediated hemolytic anemia and erythrocyte fragmentation
Variation in erythrocyte size is termed anisocytosis
Erythrocyte size
•
Macrocytes- large cells
(Anisocytosis)
•
Microcytes- small cells
• If the iron deficiency is severe, microcytosis and hypochromia may be observed on the blood film
– Spherocytes: small erythrocytes (microcyte) with no central pallor.
Macrocytic erythrocytes  Macrocytic erythrocytes are large and have an increased mean corpuscular volume (MCV)
 The most common cause of macrocytosis is an anemia
 That is characterized by increased numbers of immature erythrocytes (polychromatophilic)
 Thus hypochromasia – directly related to decreased MCV
polychromasia --- related to increased MCV
Erythrocyte shape
 Poikilocytosis - abnormal blood cells shapes
(Poikilocyte)
 The red cell membrane consists of protein (45%), lipid (45%), and carbohydrate (10%).
Poikilocytosis  Any change in these structural molecules will alter the shape, and, possibly, the flexibility of the
erythrocyte.
Echinocytes are erythrocytes with spiky protrusions from their surface.
Echinocyte
•
It has of two types;
•
crenated cells
•
acanthocytes.

Crenated cells:
– dehydrated animals
– secondary to snake bite
It also seen on blood films as an artifact when the blood film dries slowly.
schistocytes
Eccentrocytes
Keratocytes
Erythrocyte
Inclusions
1.
Heinz bodies
2. Basophilic stippling
They differ from crenated cells in several ways.
 The projections present are irregularly placed
 knobs on the tips of the spiky projections
 They generally do not retain an area of central pallor.
 Acanthocytes are thought to result from changes in decreased cholesterol or phospholipid
concentrations in the red-cell membrane
 not associated with artifact
• decreased cholesterol or phospholipid concentrations make the cells more rigid and prone to
deformation as they circulate through capillaries
• Acanthocytes are associated with several disease processes
 lipid metabolism.
 Renal disease, liver disease
 microangiopathy (formation of small fibrin clots in capillaries)
 vascular neoplasia (hemangiosarcoma)
 It is a small fragments of erythrocytes that are irregular in size and shape.
 The erythrocytes are fragmented:
 When RBC circulate through abnormal capillaries or twisted vascular channels
 In case of Turbulent blood flow
 abnormal heart valves (valvular stenosis)
 obstructions to blood flow (severe heartworm disease)
In case of microangiopathy.
 Microangiopathy is small fibrin clots (strands) formation within the capillaries
Which is associated with disseminated intravascular coagulation (DIC)
The red cell encounters a fibrin strand, and a small portion of the cell membrane is cutoff from the cell
forming a spherocyte and a small fragment (schistocyte).
Eccentrocytes are erythrocytes with fusion of a portion of the cell membrane that causes the
hemoglobin to be pushed to the side.
 Therefore one portion/side of the RBC become paler
 Oxidative injury (free radical injury) to the erythrocyte is the cause of the fusion.
 Keratocytes are erythrocytes that have small “blisters” on their surface that rupture
 Keratocytes can be seen with increased fragility, microangiopathy, and oxidative injury.
–
–
–
–
–
–
Heinz bodies are formed by oxidative injury to the hemoglobin in the erythrocyte
The hemoglobin denatures and adheres to the cell membrane,
It forms a spherical light or clear staining inclusion that may extend out from the cell membrane.
common in the cat. b/c the sulfhydryl groups in cat is more susceptible
Heinz bodies can be large or small and difficult to identify.
Significant numbers of Heinz body formation is associated with anemia because the spleen will remove
erythrocytes with Heinz bodies.
•presence of numerous basophilic granules distributed throughout the matured RBC
•It is characterized by fine basophilic endoplasmic reticulum.
•It is due to Incomplete or failure of ribosomal degradation and clearance during maturation in case of
lead and heavy metal poisoning
•Deficiency or inhibition of this enzyme causes anemia with marked basophilic stippling on peripheral
2.
smears
•Liver disease is also considered as the cause of basophilic stippling .
3. Howell-Jolly bodies
4. Nucleated
erythrocytes:
Mass appearance
of the RBC
3.
1. Rouleaux formation
Agglutination
Howell-Jolly bodies are small remnants of the erythrocyte’s nucleus
 remain after the nucleus undergoes division and cleared from the cell.
 These small fragments may not be extruded with the nucleus as the erythrocyte matures.
• Cats normally tend to have a few erythrocytes with Howell-Jolly bodies because their spleen is not as
efficient at removing abnormal erythrocytes.
Nucleus remain in erythrocytes
• It is associated with
• regenerative anemias
 early release of these cells in response to hypoxia.
• Rouleaux formation is the spontaneous association of erythrocytes in linear stacks, and its appearance is
similar to a stack of coins.
• Marked rouleaux formation is normal in horses, and a slight amount also is normal in dogs and cats.
• Rouleaux formation is enhanced when the concentration of plasma proteins such as fibrinogen or
immunoglobulins is increased.
• Rouleaux is generally associated with inflammatory conditions
•
Agglutination of erythrocytes results in irregular, spheric clumps of cells because of antibody-related
bridging
– grapelike RBC aggregates
• Agglutination is different from coagulation
• Agglutination is when Ag and Ab complex is formed
•
Agglutination is very suggestive of
•
Neutrophil Disorders
1. Neutrophilia
LEUKOCYTE
DISORDER
2. Leukemoid reaction
3. Leukoerythroblastic
reaction
4. Neutropenia
Myelodysplastic
syndromes (MDS)
Morphologic
and functional
abnormalities of
neutrophils
a. Acquired morphologic
abnormalities –
1. Toxic granulation
2. Dohle bodies
Cytoplasmic vacuoles
A. Pelger- Huet Anomaly
 ii. Inherited
functional
and/or
morphological
Leukocyte adhesion
• immune-mediated hemolytic anemia – when RBC are targeted by immune cells
• a mismatched blood transfusion – immune cells forms complex with transfused RBC
To differentiate agglutination from rouleaux, mix a small quantity of blood with a drop of isotonic
saline.
• Agglutination will persist in the presence of saline whereas rouleaux formation will disperse
• true agglutination caused by antibodies linking the erythrocytes together
• It is just to mean Agglutination is due to specific antibody and rouleaux is due to nonspecific immune
cell or proteins during inflammation
 an increase in neutrophils concentration
•
In case
• Bacterial infections (most common cause)
• Tissue destruction or drug intoxication (tissue infarctions, burns, neoplasms, uremia)
Excitement  increase secretion of epinephrine  increased rate of blood flow  “washes” neutrophils
from the storage pool into the circulating pool
 an extreme neutrophilia
Characterized by
 the presence of many bands, metamyelocytes, and myelocytes.
 occasionally promyelocytes and myeloblasts may be seen.
 promyelocytes  myeloblasts  myelocytes  metamyelocytes  bands  segmental neutrophiles
 nucleated RBCs and neutrophilic precursors are both found in the peripheral blood.
This is associated with:
 myelopthesis (proliferation of abnormal elements in the bone marrow)
Eg. fibrous tissue or malignant tumors
hemorrhage or hemolysis
To replace the lost blood cells there will be an increased production of RBCs
 low number of neutrophils
 Resulted from Decreased bone marrow production which is due to:
 Radiotherapy or chemotherapy – for tumor therapy
 myelopthesis
 inhibition of DNA synthesis of stem cells or precursor cells
 Caused by Vit B 12 or folate deficiency
o disorder in which Bone marrow’s inability to produce functional blood cells rather it produce
defective blood cells
may include abnormal in shape, size and function
The cause is not clear but chronic inflammatory diseases or DNA mutation is suspected as a causal
agents
 It is Big, Dark coarse granules found in cytoplasm of granulocytic cells, particularly in neutrophils.
 seen in cases of severe infection The presence of toxic granules indicates increase in lysosomal activity (it is why the name called toxic)
 light blue, oval, basophilic, inclusion bodies located in the peripheral cytoplasm of neutrophils.
 Döhle bodies are intra-cytoplasmic structures composed of agglutinated ribosomes and endoplasmic
reticulum.
increase in number with severe inflammation.








It is clear, unstained areas in the cytoplasm of neutrophils.
Presence of vacuolation reflects endotoxemia resulting in autolysis of neutrophils.
Toxic granulations  endotoxemia  autolysis of neutrophils.
This autodigestion is responsible for the cytoplasmic vacuolation.
It occur in the Presence of
severe infectious processes or sepsis, severe inflammatory states,
Trauma, Burns also causes cytoplasmic vacuoles.
A condition in which the neutrophil’s nucleus does not segment beyond the bilobular stage (but it is
mature)
 It does not associated with any infection
 But it is because of mutation in lamin B receptor (LBR)
 Mutations in the LBR gene are responsible for the morphologic changes in leukocytes known as the
Pelger-Huët anomaly (PHA)

3.
 Integrins
is a glycoprotein adhesion molecules on the surface of the leukocytes
 These integrins attach (bind) to ligands on the lining of blood vessels.
 This binding leads to linkage (adhesion) of the leukocyte to the blood vessel wall.
As a result, there is a decreased response to injury and delayed wound healing
abnormalities
Macrophage disorders
1. Lysosomal storage
diseases
•
•
•
•
Lysosome containing hydrolytic enzymes capable of breaking down
If the enzymes are missing or don't work properly the materials can build up and become toxic.
Synthesis of lysosomal enzymes is controlled by nuclear genes.
depending on the types of enzymes deficit there are different types of diseases.