Specialties: Hematopathology

The type-5 tartrate resistant acid phosphatase (TRAcP) is an iron-binding glycoprotein that exists in humans as distinct unprocessed and processed isoforms, 5a and 5b, respectively. TRAcP is principally expressed in cells of the monocyte lineage, including macrophages, dendritic cells, and osteoclasts, with its most well understood function being in facilitating the bone resorption process.¹ A variety of hematological disorders display TRAcP activity but antibodies developed against the protein have a particularly high sensitivity and specificity for labeling hairy cells in patient cases of hairy cell leukemia.^2-4  Anti-TRAcP has immunohistochemical utility in providing adjunctive information for the identification of hairy cell leukemia.