Lymphocytosis, or a high lymphocyte count, is common if you’ve had an infection. High lymphocyte levels that persist may point to a more serious illness or disease, such as:

Lymphocytes: Definition, Ranges,Count & Functions

There are different types of B cells and T cells that have specific roles in the body and the immune system.

for decades Memory B cells circulate in the body to start a fast antibody response when they find a foreign substance. They remain in the bodyand become memory cells, which remember previously found antigens and help the immune system respond faster to future attacks.

Regulatory B cells or Bregs make up around 0.5 percent of all B cells in healthy people. Although few in number, they have a vital role to play.

Bregs have protective anti-inflammatory effects in the body and stop lymphocytes that cause inflammation . They also interact with several other immune cells and promote the production of regulatory T cells or Tregs.

Killer or cytotoxic T cells scan the surface of cells in the body to see if they have become infected with germs, or if they have turned cancerous. If so, they kill these cells.

Helper T cells “help” other cells in the immune system to start and control the immune response against foreign substances.

There are different types of helper T cells, and some are more effective than others against different types of germs.

For instance, a Th1 cell is more effective against germs that cause infection inside other cells, such as bacteria and viruses, while a Th2 cell is more effective against germs that cause infection outside of cells, such as certain bacteria and parasites.

Tregs control or suppress other cells in the immune system. They have both helpful and harmful effects.

They maintain tolerance to germs, prevent autoimmune diseases, and limit inflammatory diseases. But they can also suppress the immune system from doing its job against certain antigens and tumors.

Memory T cells protect the body against previously found antigens. They live for a long time after an infection is over, helping the immune system to remember previous infections.

If the same germ enters the body a second time, memory T cells remember it and quickly multiply, helping the body to fight it more quickly.

Natural killer T cells are a mixed group of T cells that share characteristics of both T cells and natural killer cells. They can influence other immune cells and control immune responses against substances in the body that trigger an immune response.