Description

CD5 is a 67 kD protein, also known as Lyt-1, Ly-1, T1, Tp67, or Ly-12. It is a member of the scavenger receptor cysteine-rich protein superfamily (SRCR) and primarily expressed on thymocytes, T cells, and B-1 cells. The CD5 antigen is found on 95% of thymocytes and 72% of peripheral blood lymphocytes. In lymph nodes, the main reactivity is observed in T cell areas. Anti-CD5 is a pan Tcell marker that also reacts with a range of neoplastic Bcells,
e.g. chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), mantle cell lymphoma, and a subset (~10%) of diffuse large B-cell lymphoma. CD5  aberrant expression is useful in making a diagnosis of mature T-cell neoplasms.