What Does Low Lymph Levels Mean in Complete Blood Count?

Low lymph levels in a complete blood count refer to lymphocytopenia, which can be chronic or acute. Causes may include certain cancers, fasting, corticosteroid use, certain viral infections or certain autoimmune disorders.

Lymphocyte Types
A lymphocyte is a white blood cell in the body. They account for approximately 20 to 40 percent of a person's white cells. There are three types of this cell, including B cells, natural killer cells and T cells.

The bone marrow is always at work creating cells that eventually transform into lymphocytes. Most will go into the body's lymphatic system, but some will go to the bloodstream. The lymphatic system contains different organs and tissues, such as the spleen, lymph nodes and tonsils, all of which work to fight against infection.

B cells are in the bone marrow, and they account for approximately 15 to 25 percent of lymphocytes. T cells are in the thymus and account for about 40 to 75 percent of this white blood cell.

T and B cells might be either memory or effector cells. The memory type are able to essentially remember the past infections you have had. This can prevent re-infection with those antigens. The effector type are antigen-activated to fight an infection a person currently has.

Natural killer cells are cytotoxic. They have the ability to destroy and react against another cell in the body with ever being sensitized to it. They are the first defense against cells infected by a virus and cancer cells. They develop without help of the thymus and start in the bone marrow. They destroy cells by attaching to them and releasing chemicals with the ability to break up the cell after breaching its wall.

T and B Cell Function
B cells become plasma cells after recognizing an antigen. This makes it possible for them to fight antigens by producing the right antibodies. T cells come in three forms, including helper T cells, cytotoxic T cells and regulatory T cells.

The cytotoxic type destroy cancer cells, antigen-infected cells and foreign cells. The helper type works to direct the immune response of other T cells and of B cells. The regulatory type work to keep the immune response in check and suppress the immune system. They also work to stop the body's other white blood cells from fighting against good substances in the body, such as good gastrointestinal flora.

Lymphocytopenia Testing
A complete blood count with differential might be used to determine why lymphocyte levels are low. A doctor may take this a step further and do a T and B cell screen to look specifically at these two cell types.

All of these screening types involve taking a blood sample from a patient and then analyzing it in a laboratory. Depending on the results, further blood and other diagnostic testing might be needed. With these tests, there are certain issues that can result in inaccurate results, and patients should be clear about their medication and medical history with their doctors. For example, a recent infection, steroid therapy, current HIV, pregnancy, high stress, recent surgery and radiation or chemotherapy can cause abnormal results.