A transmembrane protein B-lymphocyte antigen CD20 is coded by the MS4A1 gene at 11q12.2 that is important in B lymphocyte differentiation into plasma cells. Dysfunctional mutations can cause immunodeficiency ( eg. common variable immunodeficiency-5 (CVID5)).
Permissive to B cell:
- Proliferation by mitogens
From early B cells to pre-B cell stage, but not plasma cells.
Significance in disease
Marker (see FMC7 monoclonal antibody) of most B-cell lymphomas (not exhaustive list):
- Mantle cell lymphoma
- Chronic lymphocytic leukaemia
- Follicular lymphoma
- Marginal zone lymphoma
- Lymphoplasmacytic lymphoma
- Diffuse large B-cell lymphoma
- Burkitt's lymphoma
Also nodular lymphocyte predominant Hodgkin's lymphoma and rare T-cell lymphomas.