High specificity of combined TRAP and DBA.44 expression for hairy cell leukemia.
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.
Went
Philip Th
PT
Institute for Pathology, University of Basel, Basel, Switzerland.
Zimpfer
Annette
A
Pehrs
Ann-Christine
AC
Sabattini
Elena
E
Pileri
Stefano A
SA
Maurer
Robert
R
Terracciano
Luigi
L
Tzankov
Alexandar
A
Sauter
Guido
G
Dirnhofer
Stephan
S
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
D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase