Lymphocytes have no granules under the microscope.
There are three basic types of lymphocytes and many subtypes.
The first two, NK or natural killers and T cells are different parts of our cell mediated or cellular immune response to threats from infections and cancers.
Our cancer, namely CLL, always arises from the third type, the B cells. These B-lymphocytes make the antibodies that float in the liquid blood and so are said to be part of the liquid or humoral immune system.
Originally published in The CLL Tribune Q3 2015