title: Myeloperoxidase immunoreactivity in adult acute lymphoblastic leukemia.
abstract: To evaluate the frequency and significance of myeloperoxidase positivity in adult acute lymphoblastic leukemia (ALL), bone marrow biopsy material from 82 adults with ALL was evaluated with a polyclonal myeloperoxidase (pMPO) antibody. Nineteen cases (23%) demonstrated evidence of pMPO immunoreactivity. Positive cases were precursor B-cell lineage, and CD13 or CD15 expression was more frequent than in the pMPO-negative cases. A subset of pMPO-positive cases studied with a monoclonal MPO antibody was negative. Western blot analysis using the pMPO antibody showed the expected 55-kd band for myeloperoxidase in pMPO-positive and pMPO-negative ALLs, suggesting a lack of specificity of this antibody in ALL. Forty-two percent (8/19) of the pMPO-positive ALL cases demonstrated evidence of t(9;22) by either karyotype or polymerase chain reaction analysis. The pMPO-positive ALLs had a lower frequency of extramedullary disease than the pMPO-negative group and a trend toward improved overall survival compared with the pMPO-negative group. Immunoreactivity with pMPO in adult ALL may lead to an incorrect interpretation of biphenotypic acute leukemia using a recently described scoring system, and a revision to that scoring system is proposed to accommodate pMPO-positive ALL.
authors.affiliation: Division of Pathology, City of Hope National Medical Center, 1500 E Duarte Rd, Duarte, CA 91010, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Arber
authors.forename: D S
authors.initials: DS
authors.lastname: Snyder
authors.forename: M
authors.initials: M
authors.lastname: Fine
authors.forename: A
authors.initials: A
authors.lastname: Dagis
authors.forename: J
authors.initials: J
authors.lastname: Niland
authors.forename: M L
authors.initials: ML
authors.lastname: Slovak
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000201:enzymology; D015153:Blotting, Western; D001853:Bone Marrow / Q000201:enzymology; D002460:Cell Line; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D016130:Immunophenotyping; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000201:enzymology* / Q000235:genetics; D013234:Stem Cells / Q000201:enzymology; D016019:Survival Analysis; D014178:Translocation, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D009195:Peroxidase