CD20 (Pan B Cell Marker)

CD20 is a transmembrane protein and a classic B‑cell marker expressed on most mature B lymphocytes from late pre‑B through memory B cells but absent on hematopoietic stem cells and plasma cells. It is involved in B‑cell activation and calcium signaling. Clinically, CD20 helps identify B‑cell populations and B‑cell lymphomas and is the target of monoclonal antibody therapy (e.g., rituximab) that depletes CD20‑positive B cells.

A pan B‑cell marker is a protein consistently expressed across most B lymphocytes, used to identify and quantify B cells in flow cytometry and tissue staining. These markers (for example CD19, CD20, CD79a, PAX5) help diagnose and classify B‑cell disorders, track treatment response, and distinguish B cells from other immune cells. Some are surface proteins; others are intracellular.

CD20 is a B‑cell surface marker on mature B lymphocytes. CD20‑positive diseases include many B‑cell malignancies: non‑Hodgkin lymphomas (diffuse large B‑cell, follicular, mantle‑cell, marginal‑zone, Burkitt), chronic lymphocytic leukemia (often CD20‑dim), hairy cell and lymphoplasmacytic/Waldenström’s, some B‑cell acute lymphoblastic leukemias, and primary CNS B‑cell lymphomas. Expression levels vary.

CD20 is a transmembrane protein expressed on most B cells (from pre-B to mature, but not on pro-B or plasma cells) that helps regulate B-cell activation, proliferation and calcium signaling. It serves as a lineage and differentiation marker and organizes membrane signaling complexes. Because of its stable surface expression and immune role, CD20 is a principal target for monoclonal antibody therapies that deplete B cells in autoimmune disease and lymphoma.

CD20 is absent on early B‑cell precursors (pro‑B cells), on antibody‑secreting plasmablasts and on terminally differentiated plasma cells. Consequently anti‑CD20 therapies spare hematopoietic stem cells and plasma cells (which maintain existing antibody production). Some transitional B cells may have low CD20, while mature naïve and memory B cells are CD20 positive.

CD20, also known by the gene name MS4A1, is a membrane‑embedded B‑cell surface antigen expressed on most mature B lymphocytes. It’s a non‑glycosylated tetra‑transmembrane phosphoprotein involved in B‑cell activation, proliferation and calcium signaling. CD20 is an important diagnostic marker and therapeutic target for anti‑B‑cell monoclonal antibody treatments in lymphoma, leukemia and autoimmune diseases.