Lymphocytes are types of white blood cells that help the immune system defend against disease and infection.
There are two main types of lymphocytes: T-cells and B-cells. T-cells fight infected cells and tell other cells to fight. B-cells make antibodies (also known as immunoglobulin or Ig) that target specific germs.
Learn more about the role of lymphocytes in primary immunodeficiency diseases (PIDD).