title: Dipeptidyl(amino)peptidase IV (DAP-IV) histochemistry on normal and pathologic lymphoid tissues.
abstract: The enzyme glycyl-proline-naphthylamidase (dipeptidyl-amino-peptidase IV), (DAP-IV) has been histochemically analysed in normal and pathological specimens of different lymphoid tissues. In all the tissues examined, the enzyme appeared to be highly specific for T cells. Using chloroformacetone fixation and sections of proper thickness, DAP-IV could be successfully demonstrated in cortical thymocytes, which exhibited weak reactivity, as well as in medullary thymocytes which showed a more intense and variable reactivity. A similar reactivity was observed in T cells of peripheral blood, lymph node, and spleen. Various acute lymphoblastic and nonlymphoblastic leukemias and malignant lymphomas were studied using the histochemical method for DAP-IV. Malignant cells from all the acute leukemias and from the B-cell lymphomas were DAP-IV unreactive, while strong reactivity was observed in one case of T-CLL and one case of T-PLL. The possible relationship of DAP-IV positivity pattern with T-cell maturation and its potential use as a diagnostic tool in lymphoproliferative disorders are discussed.
mesh_terms: D001853:Bone Marrow / Q000201:enzymology; D002648:Child; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D007938:Leukemia / Q000201:enzymology; D008198:Lymph Nodes / Q000201:enzymology; D008221:Lymphoid Tissue / Q000201:enzymology*; D008223:Lymphoma / Q000201:enzymology; D013154:Spleen / Q000201:enzymology; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D010450:Endopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases