CD8 (SP16)

Anti-CD8 is a T-cell marker for the detection of cytotoxic/suppressor lymphocytes. CD8 is also detected on NK cells, most thymocytes, a subpopulation of null cells and bone marrow cells. This antibody, along with other markers, can be used to distinguish between reactive and neoplastic T-cells.1 Expression of both CD4 (+) and CD8 (+), or lack of expression of both markers in a lymphoid population would be evidence for lymphoma.2,3 Although most T-cell lymphoma/leukemias can be either CD8+ or CD8-, CD8 positivity is a factor against Mycosis Fungoides as this entity is negative for CD8.4 Rarely does anti-CD8 label non-hematolymphoid neoplasms.5