{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T19:11:51Z","timestamp":1775675511789,"version":"3.50.1"},"reference-count":13,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2018,1,17]],"date-time":"2018-01-17T00:00:00Z","timestamp":1516147200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"name":"Children's Hospital of Michigan Foundation and Kids without Cancer Foundation"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cytometry Part B Clinical"],"published-print":{"date-parts":[[2018,5]]},"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Flow cytometric intracellular myeloperoxidase (MPO) staining of leukemic blasts is a useful tool in diagnosis of leukemia subtype. Interpretation of high MPO\u2010positivity can be a diagnostic challenge in B\u2010lineage acute lymphoblastic leukemia (B\u2010ALL). While very few such cases have been reported, high MPO positive B\u2010ALL cases without additional myeloid antigen positivity are suspect and require further investigation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Three pediatric cases of B\u2010ALL with strong MPO staining (clone 8E6; Invitrogen) at diagnosis and three others with negative MPO staining were studied by flow cytometry and immunohistochemistry. In\u2010vitro drug cytotoxicity, oxidative stress generation, and immunophenotyping using other MPO clones were performed to further investigate MPO presence.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Expectedly, normal myeloid cells in all six samples were positive and mature lymphocytes negative for MPO staining. However, MPO monoclonal antibody (mAb) obtained from clones other than Invitrogen and other myeloid\u2010specific mAbs gave negative results suggesting false positivity of the initial MPO staining. Immunohistochemistry for MPO was also negative on all six cases tested. Furthermore, in\u2010vitro vincristine cytotoxicity was greater in leukemic cells from MPO false\u2010positive cases compared with MPO\u2010negative B\u2010ALL samples, demonstrating indirect lack of MPO activity. Moreover, drug treatment did not lead to generation of reactive oxidative species, also reflective of lack of significant MPO presence.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The cause of false\u2010positive MPO staining remains unknown in these three cases; a cross reactivity could be the culprit. Caution should be given to similar phenomena and detailed investigation may contribute to the understanding of altered protein expression in such outlier cases. \u00a9 2017 International Clinical Cytometry Society<\/jats:p><\/jats:sec>","DOI":"10.1002\/cyto.b.21613","type":"journal-article","created":{"date-parts":[[2017,12,16]],"date-time":"2017-12-16T21:47:28Z","timestamp":1513460848000},"page":"477-483","source":"Crossref","is-referenced-by-count":10,"title":["Flow cytometric false myeloperoxidase\u2010positive childhood B\u2010lineage acute lymphoblastic leukemia"],"prefix":"10.1002","volume":"94","author":[{"given":"S\u00fcreyya","family":"Sava\u015fan","sequence":"first","affiliation":[{"name":"Division of Hematology\/Oncology Carmen and Ann Adams Department of Pediatrics, Children's Hospital of Michigan Detroit Michigan"},{"name":"Hematology\/Oncology Flow Cytometry Laboratory Children's Hospital of Michigan, Carmen and Ann Adams Department of Pediatrics Detroit Michigan"},{"name":"Blood and Marrow Transplant Program, Children's Hospital of Michigan, Carmen and Ann Adams Department of Pediatrics, Barbara Ann Karmanos Cancer Center Wayne State University School of Medicine Detroit Michigan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Steven","family":"Buck","sequence":"additional","affiliation":[{"name":"Division of Hematology\/Oncology Carmen and Ann Adams Department of Pediatrics, Children's Hospital of Michigan Detroit Michigan"},{"name":"Hematology\/Oncology Flow Cytometry Laboratory Children's Hospital of Michigan, Carmen and Ann Adams Department of Pediatrics Detroit Michigan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8366-9487","authenticated-orcid":false,"given":"Manisha","family":"Gadgeel","sequence":"additional","affiliation":[{"name":"Division of Hematology\/Oncology Carmen and Ann Adams Department of Pediatrics, Children's Hospital of Michigan Detroit Michigan"},{"name":"Hematology\/Oncology Flow Cytometry Laboratory Children's Hospital of Michigan, Carmen and Ann Adams Department of Pediatrics Detroit Michigan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ali","family":"Gabali","sequence":"additional","affiliation":[{"name":"Department of Pathology Wayne State University School of Medicine Detroit Michigan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2018,1,17]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2016-03-643544"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1309\/AJCPSTU55DRQEGTE"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/bjh.12277"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1096-8652(199602)51:2<147::AID-AJH9>3.0.CO;2-Y"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1309\/AJCPZ7E9IMXVSNPT"},{"key":"e_1_2_6_7_1","first-page":"335","article-title":"Myeloid cell\u2010associated lysosomal proteins as flow cytometry markers for leukocyte lineage classification","volume":"18","author":"Strobl H","year":"2004","journal-title":"J Biol Regul Homeost 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