White blood cells (WBC) play a significant role in the immune system by protecting the body from
infectious disease and foreign invaders
White blood cells (WBCs) classification is an important step because it can assist hematologists in the
diagnosing several blood disorders, such as leukemia, some immunological disorders, and certain types
of cancer
The analysis procedure can be done by automatic and manual approaches to count and classify WBC.
Manual classification of WBC has many medical difficulties, including error in the accuracy of results due
to sampling errors and statistical probabilities and poor sensitivity, specificity and predictive values
WBCs are produced from the bone marrow and found in the blood and lymphatic system. A WBC has a
nucleus, which often large and lobed, and it helps to distinguish WBC from the other blood cells. Each
WBC structure consists of a nucleus, cytoplasm and cell wall [
The Main types of WBC are: Granulocytes, Monocytes and Lymphocytes. There are seven sub-types
developed from these types. Granulocytes can be classified into Band neutrophils, Basophils or
Eosinophils. Monocytes can be classified into Macrophages or Dendritic cells, and Lymphocytes can be
classified into B-lymphocytes or Tlymphocytes (
DISCUSSION
Blood is a specialized body fluid. Its main components are red blood cells, plasma, platelets, and white
blood cells. WBCs protect the body from infections, accounting for about 1% of human blood [1], [2].
Basophils, Eosinophils, Lymphocytes, Monocytes, and Neutrophils are the types of white blood cells,
Basophils white blood cells accounting only around 1%, they are important in mounting a nonspecific
immune response to pathogens. Eosinophils play an important role in fighting bacteria and responding
to infections with parasites. Lymphocytes are also very important in the immune system, they are 2
types: B and T lymphocytes, with B cells producing antibodies, T cells being responsible for directly
killing many foreign invaders. Monocytes are responsible for cleaning up dead cells. Roughly half of the
white blood cells are Neutrophils; they are usually the first cells of the immune system to respond to an
invader such as a bacterium or a virus
White blood cells (WBCs) classification is an important step because it can assist hematologists in the
diagnosis of several blood disorders, such as leukemia, some immunological disorders, and certain types
of cancer. The analysis procedure can be done by automatic and manual approaches to count and
classify WBC. The manual classification of WBC has many medical difficulties, including error in the
accuracy of results due to sampling errors and statistical probabilities and poor sensitivity, specificity,
and predictive values. Furthermore, some automatic approaches in the laboratories have used
instruments, such as flow cytometry and automatic counting machine to detect and classify WBC. These
instruments do not make use of image processing techniques, and they can count and classify WBCs
quantitatively not qualitatively
In the differential leucocyte count (DLC) the
percentage of each type of white blood cells in
the total leucocyte population is determined.
Each type of white cells, performs a different
function in the battle against infections and
each type of infection yields a different white
cell picture in the blood. The morphology and
staining characteristics of each type is peculiar
and is responsible for the in specific typing.
In the differential leucocyte count (DLC) the
percentage of each type of white blood cells in
the total leucocyte population is determined.
Each type of white cells, performs a different
function in the battle against infections and
each type of infection yields a different white
cell picture in the blood. The morphology and
staining characteristics of each type is peculiar
and is responsible for the in specific typing.
Reference ranges for differential white blood cell counts are as follows [1] :
Neutrophils - 2500-8000 per mm3 (55-70%)
Lymphocytes - 1000-4000 per mm3 (20–40%)
Monocytes - 100-700 per mm3 (2–8%)
Eosinophils - 50-500 per mm3 (1–4%)
Basophils - 25-100 per mm3 (0.5-1%)
The Leukocyte Differential Count is the determination of the proportion of, or absolute count per unit
volume of defined classes or subsets of leukocytes in a blood sample41 ,42, 51. The purpose of the
differential count is to obtain a picture of the true distribution of the leukocytes in peripheral blood3 .
This is used by clinicians to determine the disease status of their patients. The leukocytes present in the
peripheral blood are composed of five types of mature cells, i.e. neutrophils, lymphocytes, monocytes,
eosinophils and basophils
Clinical Significance
Leukocyte Disorders blood disorders, such as leukemia, some immunological disorders, and certain
types of cancer
WBC disorders can be classified as quantitative or qualitative. In quantitative alterations all cells appear
normal but are present in abnormal quantities, either in excess or in defect of normal values. In
qualitative defects, abnormal appearing cells or extrinsic cells are found in circulation
Granulocytes can be increased in circulation by four different mechanisms: increased production,
decreased egress from the circulation, demargination, and release from storage compartments.
Most instances of neutrophilia are secondary to a pathologic process outside the marrow. It can occur in
infectious diseases, especially acute bacterial infections; neoplasia, either affecting the myeloid system
(chronic myelogenous leukemia and other myeloproliferative disorders) or secondary to a solid tumor
(paraneoplastic syndrome); inflammation secondary to tissue necrosis, metabolic and collagen diseases,
hypersensitivity reactions; hemorrhage; hemolysis; and stress.
Neutropenia is due in the great majority of cases to decreased production of granulocytes.
Antineoplastic agents and extensive radiation therapy produce neutropenia almost invariably. Drugs
such as phenothiazines, phenylbutazone, and allopurinol can induce neutropenia through idiosyncratic
reactions. Infections, most often viral but also bacterial or rickettsial, can lower the polymorphonuclear
count. Other conditions causing a decrease in WBC production include cyclic neutropenia, congenital
disorders, and idiopathic neutropenia.
If peripheral consumption exceeds production, neutropenia and concomitant marrow hypercellularity
will result. It can be seen in hypersplenism, Felty's syndrome, and in the presence of antineutrophil
antibodies.
The risk of infection increases when the absolute granulocyte count falls below 1000 per microliter.
Gram-negative sepsis is common in this setting
Monocytosis can follow chronic infectious disorders (tuberculosis, brucellosis), rheumatic
diseases (lupus, rheumatoid arthritis), chronic inflammatory bowel disease, and some malignant
processes (Hodgkin's and non-Hodgkin's lymphoma). Monocytes play an important role in other
chronic granulomatous diseases: sarcoidosis, histiocytosis X, and storage diseases (Gaucher's
disease, Niemann–Pick disease).
Eosinophilia occurs in association with hypersensitivity reactions, parasitic infestations, cancers
(Hodgkin's disease, eosinophilic leukemia), connective tissue disorders (rheumatoid arthritis,
polyarteritis nodosa), and the syndrome of pulmonary infiltrates with eosinophilia.
Basophilia can be found in chronic myelogenous leukemia and other myeloproliferative
disorders, Hodgkin's disease, and some chronic inflammatory and infectious disorders.
Lymphocytopenia can be seen mainly in association with several congenital diseases of the
immune system or following treatment with corticosteroids, antineoplastic agents, or
radiation. Lymphocytosis can accompany some infections, both acute and chronic, usually viral,
Addison's disease, and autoimmune diseases
5. Conclusion
White blood cells are an important component in the human blood. All white blood cells have nuclei,
which distinguishes them from the other blood cells and also between white blood cell types and
subtypes themselves. In this Chapter, white blood cell types and their structure are reviewed
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Middle East and Africa Conference on Biomedical Engineering (MECBME), Amman,
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Cline MJ, Hutton JJ. Hematology and oncology. In: Stein JH, ed. Internal medicine. Boston: Little,
Brown, 1983
Brown, A. K. (1983). The Science and Practice of Clinical Medicine. Volume 6.
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