Viral infections.

[konfolut]

Why the number of leukocytes decreases during majority of viral infections?

[admin]

Hi are you talking about the total WBC (white blood cell) count number during a routine blood test (FBC = full blood count); or the specific subtype number(s)?

Note that the WBC Count measures two things: the total number of WBC's (leukocytes), and the differential count.

Sub-types of WBCs:
Neutrophil
Eosinophil
Basophil
Lymphocytes
Monocyte

Lymphocyte numbers should go up in time after a viral infection/innoculation as they (T-cells and B-cells) are most involved in the immune response but monocytes also work with the antibody response in clearing bound virus. Note the differential count will change after infection (specific types of cells will be more active/produced)

Note there is also a white cell shift (left or right) but this is a different topic.

[Zagami]

Leucopenia, or low white blood cell (leukocytes) count, is commonly defined in adults, as less than 3,500 white blood cells per microliter of blood, but this number may vary slightly among individuals. Infections can cause low white blood cell counts by overwhelming or using up white blood cells faster than they can be produced or disrupting bone marrow function. In some viral and parasitic infections can specifically lower white blood cells count in the blood, characterized by neutropenia and lymphocytosis. Nevertheless, an elevation in neutrophil and a decrease in lymphocyte counts are seen in peripheral blood leukocytes on the first day of illness, but conunts return to normal in 1 or 2 days. In advanced phase of the viral disease the viruses disturbs temporarily the proliferative activity of bone marrow stromal fibroblasts involved in regulation of bone marrow hemopoiesis with disrupt bone marrow function or overwhelming infections that use up white blood cells faster than they can be produced, and still some anti-viral drugs destroy white blood cells or damage bone marrow.