B cells

by Jason Wasserman MD PhD FRCPC
May 26, 2022

What are B cells?

B cells (also called B lymphocytes) are a type of white blood cell and a part of the immune system. B cells come from hematopoietic stem cells found in the bone marrow. These cells are called stem cells because they give rise to all the cells in the blood and immune system. Many B cells are found in lymphoid organs such as lymph nodes which are found throughout the body. Large numbers of B cells can also be found in an area of inflammation caused by infection or injury.

What is the function of a B cell?

B cells contribute to a process called the adaptive immune response that is important for protecting the body against infections. Specifically, B cells contribute to humoral immunity by producing immunoglobulin (antibodies) that recognize and stick to chemicals that are not normally produced in the body – such as those made by viruses. A plasma cell is a type of B cell that has been activated in the past and is capable of producing one type of immunoglobulin.

What markers are used to identify B cells?

Common markers used to identify B cells include CD20 and CD79a. Pathologists perform tests such as immunohistochemistry and flow cytometry to see B cells making CD20 and CD79a.

What types of cancer are made up of B cells?

Most cancers made up of B cells are part of a group of cancers called lymphoma. The most common types of B cell lymphoma are small lymphocytic lymphoma, follicular lymphoma, diffuse large B cell lymphoma, mantle cell lymphoma, and marginal zone lymphoma.

What types of cancer are made up of plasma cells?

Plasma cell myeloma and plasmacytoma are types of cancers made up of plasma cells.