There may be an increase in lymphocytes and leukocytes in the blood count during a viral infection, mainly due to the immune response in the body caused by the invasion of the virus.
Viral infection refers to the process by which a virus invades the human body through a number of routes and proliferates in the cells of a susceptible host. After a virus enters the body, it induces the body’s immune system to produce the appropriate cells to resist its invasion, and white blood cells and lymphocytes are the main type of immune cells, so their numbers are usually increased.
For example, an increase in lymphocytes can be seen in human herpesvirus infections, cytomegalovirus, viral hepatitis, adenovirus infections, measles, rubella, chickenpox, mumps and other diseases. There is also an increase in white blood cells if there is a combination of viral infection with bacterial infection.
However, not all lymphocytosis is indicative of viral infections, and a single increase in a certain index is not conclusive, and usually needs to be combined with other auxiliary tests to clarify.