Plasma Cell Structure and Development
- Plasma cells have basophilic cytoplasm and an eccentric nucleus with heterochromatin in a characteristic cartwheel or clock face arrangement.
- They have abundant rough endoplasmic reticulum and a well-developed Golgi apparatus for secreting immunoglobulins.
- Other organelles in a plasma cell include ribosomes, lysosomes, mitochondria, and the plasma membrane.
- B cells act as antigen-presenting cells and internalize antigens.
- T cells activate B cells, leading to differentiation into plasma cells.
- Germinal center B cells may differentiate into memory B cells or plasma cells.
- B cells undergo affinity maturation to produce antibodies of higher affinity.

Surface Antigens and Function of Plasma Cells
- Plasma cells express CD138, CD78, and the Interleukin-6 receptor.
- CD27 is a good marker for plasma cells.
- CD319 (SLAMF7) is expressed at high levels on normal and malignant plasma cells.
- Plasma cells cannot switch antibody classes or act as antigen-presenting cells.
- Lifespan, antibody class, and location of plasma cells depend on signals received from T cells.
- T cell-independent antigen stimulation results in short-lived plasma cells producing IgM antibodies.
- T cell-dependent processes produce longer-lived plasma cells producing IgG and IgA antibodies.
- Plasma cells can produce a single kind of antibody in a single class of immunoglobulin.

Survival Mechanisms and Antibody Production of Long-Lived Plasma Cells
- IL-6, TNF-α, stromal cell-derived factor-1α, and signalling via CD44 contribute to the survival of long-lived plasma cells (LLPC).
- LLPC can be found in gut-associated lymphoid tissue (GALT) and nasal-associated lymphoid tissues (NALT), suggesting the existence of tissue-specific survival niches.
- LLPC in the gut may not necessarily be generated de novo from active B cells.
- The absence of antigens and depletion of B cells do not affect the production of high-affinity antibodies by LLPC.
- LLPC in the bone marrow are the main source of circulating IgG in humans.
- LLPC in bone marrow produce high levels of IgG independently of B cells.
- Some plasma cells in bone marrow also produce IgA and IgM.
- LLPC play a role in mucosal immunity by producing IgA antibodies in GALT.
- LLPC contribute to the production of high-affinity antibodies in the absence of B cells.

Clinical Significance of Plasma Cells
- Plasmacytoma, multiple myeloma, Waldenström macroglobulinemia, heavy chain disease, and plasma cell leukemia are cancers of the plasma cells.
- Multiple myeloma is often identified by the continued production of an antibody, detectable as a paraprotein.
- Monoclonal gammopathy of undetermined significance (MGUS) can lead to multiple myeloma and is characterised by the secretion of a myeloma protein.
- Common variable immunodeficiency is associated with a problem in the differentiation from lymphocytes to plasma cells, resulting in low serum antibody levels and increased infection risk.
- Primary amyloidosis (AL) is caused by the deposition of excess immunoglobulin light chains secreted by plasma cells.

Related Concepts and References
- Plasmacytoma and multiple myeloma are plasma cell dyscrasias.
- Leukocyte and plasma cell dyscrasia are related terms to plasma cells.
- The textbook 'Guyton and Hall Textbook of Medical Physiology' discusses plasma cells.
- 'Plasma Cell - an overview' is a topic covered in ScienceDirect Topics.
- 'Plasma Cell - biology' is a topic covered in Britannica.com.
- 'Plasma Cell - LabCE.com, Laboratory Continuing Education' is a topic covered on www.labce.com.
- 'Textbook of Immunology' (2nd edition) by Bona C, Bonilla FA, and Soohoo M provides information on plasma cells.
- 'Current Protocols in Cytometry' (Chapter 6: Unit 6.23) by Rawstron AC discusses immunophenotyping of plasma cells.
- 'Blood' (123(9): 1336–40) by Frigyesi I et al. provides insights into the isolation of malignant plasma cells in multiple myeloma.