The immune system is a combination of organs and cells that protect the body from infection and other diseases by fighting harmful pathogens. The immune system includes white blood cells, lymph nodes, the spleen, bone marrow, and other organs and tissues.
TYPES OF LYMPHOCYTES
Lymphocytes are a type of immune cell that’s made in the bone marrow and found in the blood and in lymph tissue.
Three types of lymphocytes are B cells, T cells, and natural killer (NK) cells. Lymphocytes are also called white blood cells.
Help protect the body against bacteria and viruses by making antibodies that help the immune system recognize these pathogens and allow T cells to attack them.
The 2 major types of T cells are helper T cells and cytotoxic T cells. Helper cells assist other cells in the immune system. Cytotoxic T cells attack cells infected by pathogens.
NK cells are a type of immune cell
that attack tumor cells or
cells infected with a virus.
When the immune system is healthy, it protects the body not only from infection, but can also identify cancerous and/or precancerous cells and eliminate them before they can cause harm, in a process called immune surveillance. Immune cells responsible for attacking cancer cells include T cells and NK cells.
When the immune system doesn’t function optimally due to lymphoma, T cells and NK cells can fail to either detect or destroy the cancerous cells, including non-Hodgkin’s lymphoma (NHL) cells. Cancer cells also promote preferential growth of regulatory T cells, suppressing T cell activity and resulting in further immune dysfunction.