1. Leukocytes

Leukocytes (white blood cells) are cells of the immune system. They are formed in the bone marrow and are found in the blood, lymph, lymphoid organs and some tissues. The number of circulating leukocytes increases in case of infection or inflammatory reaction, so it is for this reason that their analysis is very useful.

• In the event of anomalies:

Too many leukocytes can correspond to inflammation or much more rarely to leukemia.

A decrease in white blood cells can suggest certain viral or parasitic infections, as well as anemia and certain cancers. Coupled with a decrease in red blood cells, it generally appears in the case of diseases affecting the bone marrow (myelofibrosis, aplastic anemia) or Acquired Immunodeficiency Syndrome (AIDS). More rarely, it can also result from a lack of vitamin B12, irradiation or the use of certain drugs (antibiotics, colchicine, blood pressure medications).

2. Polynuclear neutrophils

Polynuclear cells (now called granulocytes) are white blood cells qualified as “non-specific” because they are not directed towards a single antigen. There are three different ones.

Polynuclear neutrophils are phagocytes, that is to say they are able to swallow and digest foreign bodies in the body. They will therefore be found in areas of inflammation.

Their normal number is 1 to 800 / mm³ de sang.

• In the event of anomalies:

The possible diagnoses of a decrease are numerous:

– certain viral or parasitic infections,

– aplastic anemia, hyperthyroidism,

– anemia due to iron, folic acid or vitamin B12 deficiency,

– acute leukemia, myelo-dysplastic syndrome,

– agranulocytosis of toxic or medicinal, immunological or constitutional origin.

Those of an increase are just as important:

– bacterial infections caused by pyogenic germs (streptococci, staphylococci),

– inflammatory diseases (rheumatoid arthritis, ankylosing spondylitis, etc.),

– certain parasitoses,

– myocardial infarction,

– the cancer,

– Hodgkin’s disease,

– metabolic disorders: gout, uremia, eclampsia, etc.

– myeloproliferative syndromes,

– hemorrhages,

– poisoning: certain drugs, benzene, radiation, etc.

– excessive tobacco consumption.

3. Eosinophils

The role of eosinophils is to attack the parasites of the organism, without phagocyte them: they attach themselves to them, pour out their granules which contain enzymes intended to destroy them.

For a healthy person, the number of eosinophils should be less than 500 / mm³ de sang.

• In the event of anomalies:

If their number increases, this is often due to a parasitic disease (scabies, helminthiasis, etc.). However, other causes are possible:

– Allergies (asthma, eczema, urticaria, etc.),

– Leukemia and cancers,

– Skin diseases (pemphigus and polymyositis),

– Inflammatory diseases (lupus, sarcoidosis, Chur-Strauss syndrome).

4. Basophils

Polynuclear basophils are the rarest white blood cells. They activate the inflammatory reaction and intervene in allergic reactions.

Their number rarely exceeds 100 / mm³.

• In the event of anomalies:

An excess of polynuclear basophils is relatively rare and is difficult to interpret. It can indicate an allergic reaction, tumor or infectious diseases.

5. Lymphocytes

Lymphocytes play a major role in the immune system and are involved in the production of antibodies.

The normal proportion is estimated to vary from 1000 to 4000 / mm³.

• In the event of anomalies:

Their increase is observed in many viral diseases (whooping cough, mumps, brucellosis, influenza etc…) and bacterial, mononucleosis but also in leukemia.

On the contrary, their reduction will rather reflect bone marrow aplasia, congenital immune deficiencies, or even Hodgkin’s disease.

6. Monocytes

The monocytes are white blood cells that evolve into macrophages or dendritic cells. These are the largest cells in the blood.

For a healthy individual, their number varies from 160 to 1000 / mm³.

• In case of anomalies?

Their number increases in certain diseases such as mononucleosis, following anemia or in the case of chronic infections (such as chlamydiose).