CD16 (SP175)
CD16 is a biomarker associated with monocytes and natural killer (NK) cells of the lymphoid lineage.1 Anti-CD16 immunohistochemistry is useful in differentially diagnosing hepatosplenic gamma delta T-cell lymphoma and gamma delta T-cell large granular lymphocyte leukemia from other peripheral T-cell lymphomas, such as mucosal and cutaneous gamma delta T-cell lymphoma.2-4 It is reported that 58% of hepatosplenic gamma delta T-cell lymphomas express CD16, and 86% of gamma delta T-cell large granular lymphocyte leukemias are immunoreactive with anti-CD16.2-3 Mucosal and cutaneous gamma delta T-cell lymphomas usually do not express CD16 antigen.4 A significant decrease can be seen in the number of granulocytes expressing CD16 in chronic myelomonocytic leukemia compared to chronic myelogenous leukemia and control bone marrow biopsy, probably related to dysgranulopoiesis.5 Bone marrow biopsy immunohistochemistry can be helpful in CMML by identifying both the monocyte expansion and the dysgranulopoiesis with anti-CD16.5