The lymph system (also known as the lymphatic system) is composed of lymphoid tissue, lymph vessels, and clear interstitial fluid found between cells called lymph. Lymphoid tissue is composed of several types of immune cells that work together to help fight bodily infections. Lymphoid tissue is found throughout the body:

Lymphocytes

Lymphocytes are cells in the lymphoid tissue, a type of white blood cells. The 2 types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells). Both can develop into lymphoma cells, but taking into consideration that B-cell lymphomas are much more common than T-cell lymphomas.

B lymphocytes

B-cells protect the body against germs by producing antibodies. Antibodies attach to bacteria or viruses attracting other immune system cells that surround and digest the antibody-coated germ.

T lymphocytes

There are several different types of T-cells, each with a specialized job. Some protect the body against viruses, fungi, and bacteria. They also release a substance called cytokines to attract other types of white blood cells, which then ingest infected cells.

Organs containing lymphoid tissue

Lymphoid tissue is in many parts of the body making it lymphomas possible. The major organs with lymphoid tissue are:

Lymph nodes

Lymph nodes are organs found throughout the body, and act as filter for foreign particles. They contain white blood cells and are connected by a system of lymphatic vessels. These vessels (like viens) carry lymph and immune system cells.

Lymph nodes grow when fighting infections. Lymph nodes that grow in reaction to infection are called reactive nodes or hyperplastic nodes—usually tender to the touch. Enlarged lymph nodes are not always a sign of a serious problem. But a large lymph node is also the most common sign of lymphoma.

Spleen

The spleen creates lymphocytes and other immune system cells to help fight infections. It stores healthy blood cells and filters out damaged blood cells, bacteria, and cell waste.

Thymus

The thymus plays a vital role in the development of T-cells. T cells emigrate from the thymus and constitute the peripheral T cell repertoire responsible for directing many facets of the adaptive immune system.

Tonsils

Tonsils are located in the back of the throat and help create antibodies fighting germs that are breathed or swallowed.

Digestive tract

The stomach and intestines as well as many organs also contain lymphoid tissue.

Bone Marrow

The bone marrow creates red blood cells, blood platelets, and white blood cells. Bone marrow lymphocytes are primarily B-cells. Lymphomas can start from bone marrow lymphocytes.