title: High specificity of combined TRAP and DBA.44 expression for hairy cell leukemia.
abstract: Because of marrow fibrosis, bone marrow aspirations are often nonconclusive in patients with hairy cell leukemia (HCL). Therefore, histologic examination is important in HCL but often difficult in cases with low numbers of tumor cells. A combined immunohistochemical positivity for DBA.44 and tartrate-resistant phosphatase was previously found in 100% of HCL and suggested to be specific for this diagnosis. To further assess the diagnostic specificity and sensitivity of this immunohistochemical approach in a higher number of cases, we analyzed 56 HCLs and lymphoma tissue microarrays, including 840 cases of the most frequent non-Hodgkin lymphomas. All HCLs showed combined positivity for these two proteins (100% sensitivity). Both antibodies were often positive in other lymphoma types. DBA.44 reactivity was especially frequent in follicular lymphomas (46%), whereas tartrate-resistant acid phosphatase (TRAP) expression was often seen in mantle cell lymphomas (57%), primary mediastinal large B-cell lymphomas (54%), and chronic lymphocytic leukemia/small lymphocytic lymphoma (41%). A combined DBA.44/TRAP positivity was seen in only 3% of non-HCL non-Hodgkin lymphomas, including cases of diffuse large B-cell lymphomas, follicular lymphomas, chronic lymphatic leukemia/small lymphocytic leukemias, and mantle cell lymphomas. Overall, these data confirm the utility of combined immunohistochemical DBA.44/TRAP expression analysis in confirming the diagnosis of HCL. However, combined positivity for these markers is highly sensitive but not absolutely specific for HCL.
authors.affiliation: Institute for Pathology, University of Basel, Basel, Switzerland.
authors.forename: Philip Th
authors.initials: PT
authors.lastname: Went
authors.forename: Annette
authors.initials: A
authors.lastname: Zimpfer
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Pehrs
authors.forename: Elena
authors.initials: E
authors.lastname: Sabattini
authors.forename: Stefano A
authors.initials: SA
authors.lastname: Pileri
authors.forename: Robert
authors.initials: R
authors.lastname: Maurer
authors.forename: Luigi
authors.initials: L
authors.lastname: Terracciano
authors.forename: Alexandar
authors.initials: A
authors.lastname: Tzankov
authors.forename: Guido
authors.initials: G
authors.lastname: Sauter
authors.forename: Stephan
authors.initials: S
authors.lastname: Dirnhofer
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000378:metabolism*; D007943:Leukemia, Hairy Cell / Q000378:metabolism* / Q000473:pathology; D008228:Lymphoma, Non-Hodgkin / Q000378:metabolism* / Q000473:pathology; D012680:Sensitivity and Specificity; D000071681:Tartrate-Resistant Acid Phosphatase; D046888:Tissue Array Analysis
chemical_list: D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase