CD61 (Megakaryocytic Cell Marker)

CD61 is the designation for integrin β3, a cell-surface marker mainly expressed on platelets and megakaryocytes. It forms part of the GPIIb/IIIa (αIIbβ3) complex involved in platelet adhesion and aggregation. CD61 is also detected on some endothelial cells and in megakaryocytic-lineage leukemias, so it’s used diagnostically to identify platelet/megakaryocyte differentiation.

Megakaryocytes characteristically express CD41 (integrin αIIb), CD61 (integrin β3) and CD42 (glycoprotein Ib complex). CD41/CD61 form the αIIbβ3 integrin commonly used to identify megakaryocytic lineage and platelets, while CD42 is associated with more mature megakaryocytes. These markers are routinely applied in flow cytometry and immunohistochemistry to study megakaryocyte development.

CD61 is another name for integrin beta-3 (ITGB3), also called platelet glycoprotein IIIa (GPIIIa). It pairs with integrin alpha-IIb (CD41/GPIIb) to form the platelet fibrinogen receptor complex (GPIIb/IIIa), which mediates platelet aggregation and adhesion. Mutations or antibodies to CD61 can affect clotting and contribute to thrombotic or bleeding disorders.

CD41 and CD61 are surface proteins that pair to form the integrin αIIbβ3 receptor on platelets and megakaryocytes. This receptor binds fibrinogen and von Willebrand factor to enable platelet aggregation and clot formation. Flow cytometry measures CD41/CD61 to assess platelet count and function; inherited absence or dysfunction causes bleeding disorders such as Glanzmann thrombasthenia and can inform thrombotic risk.

Lactate dehydrogenase (LDH) is the most commonly used blood marker for many leukemias and lymphomas; elevated LDH often reflects high tumor burden and poorer prognosis. Diagnosis and subtyping depend on additional markers—cytogenetic abnormalities (e.g., BCR‑ABL in CML) and immunophenotyping (CD markers such as CD19, CD20, CD34)—so LDH is a general activity/prognostic marker, not disease-specific.

CD61 is the cluster-of-differentiation designation for the ITGB3 gene, which encodes integrin beta-3 (also called glycoprotein IIIa). This protein pairs with integrin alpha subunits (notably αIIb) to form the fibrinogen receptor αIIbβ3 on platelets, crucial for platelet adhesion, aggregation and coagulation; mutations can alter bleeding and thrombosis risk.