A cell surface-associated protein expressed at high levels in helper T-cells and at lower levels in monocytes., including Langerhans and other dendritic cells. It is absent from immature thymocytes, but most mature T-cell lymphomas are positive with the exception of aggressive NK-cell leukemia, extranodal NK-cell lymphoma, gamma delta T-cell lymphomas, and enteropathy-type T-cell lymphoma. It is also the receptor for HIV.
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen typeorOne (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody orderedBlock and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.