Histopathology of centrocytes in follicular lymphoma

A centrocyte generally refers to a

B cell B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or ...

with a cleaved nucleus, as may appear in e.g.

follicular lymphoma Follicular lymphoma (FL) is a cancer that involves certain types of white blood cells known as lymphocytes. The cancer originates from the uncontrolled division of specific types of B-cells known as centrocytes and centroblasts. These cells normal ...

.Table 12-8 in: 8th edition. Centrocytes are B cells that are found in the light zones of

germinal center Germinal centers or germinal centres (GCs) are transiently formed structures within B cell zone (follicles) in secondary lymphoid organs – lymph nodes, ileal Peyer's patches, and the spleen – where mature B cells are activated, prolifera ...

s. Centrocytes are the non-dividing progeny of

Centroblasts A centroblast generally refers to an activated B cell that is enlarged (12–18 micrometer) and is rapidly proliferating in the germinal center of a lymphoid follicle. They are specifically located in the dark zone of the germinal center. Cent ...

, and although they are relatively similar in size, centrocytes lack distinct nucleoli and are more irregularly shaped than centroblasts Centrocytes also express the cell-surface hypermutated B-cell receptor following AID activation. This hypermutated B-cell receptor allows centrocytes to compete for binding of the antigen, internalize it, and then express the processed peptides through their

MHC class II MHC Class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial ce ...

receptor. Centrocyte can also refer to a cell with a protoplasm that contains single and double granules of varying size stainable with hematoxylin, as seen in lesions of

lichen planus Lichen planus (LP) is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, and is only named that because it looks like one. It is characterized by polygonal, fla ...

, or a nondividing, activated B cell that expresses membrane immunoglobulin.

Development

Centrocyte, centroblast and follicular dendritic cell in a follicular lymphoma

The dark zone of germinal centers contain proliferating centroblasts. Once these centroblasts are stimulated, they no longer divide, and proceed to move to the light zone of germinal centers. In the light zone, T follicular helper cells mediate centrocyte selection through

CD40L CD154, also called CD40 ligand or CD40L, is a protein that is primarily expressed on activated T cells and is a member of the TNF superfamily of molecules. It binds to CD40 on antigen-presenting cells (APC), which leads to many effects dependin ...

and provide them with pro-survival signals. The centrocytes to compete for T follicular helper cell and dendritic cell help, allowing for selectivity towards centrocytes that bind to antigen with higher affinity. Centrocytes with high affinity are allowed to exit the germinal center as

memory B cell In immunology, a memory B cell (MBC) is a type of B lymphocyte that forms part of the adaptive immune system. These cells develop within germinal centers of the secondary lymphoid organs. Memory B cells circulate in the blood stream in a quiescen ...

s or long-lived

plasma cell Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B lymphocytes and secrete large quantities of proteins called antibodies in response to being presented specific substan ...

s, while other selected centrocytes are allowed to reenter the cell cycle by

T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...

s. The remaining centrocytes undergo apoptosis or return to the centroblast pool for further

somatic hypermutation Somatic hypermutation (or SHM) is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it (e.g. microbes), as seen during class switching. A major component of the process of affinity maturation, SHM div ...

. Centrocytes that do not recognize antigen properly due to an altered B cell receptor will undergo apoptosis.

References

Lymphocytes {{Lymphatic-stub