medical and biological sciences - Collegium Medicum - Uniwersytet ...

Quantitative analysis of changes in expression of leukemic markers during short-term prednisolone therapy in vitro 53The initial response of leukemia cells to treatmenthas consistently been shown to be a reliable prognosticindicator, and its evaluation has been significantlyenhanced by methods that allow detection of submicroscopiclevels of leukemia, defined as minimal residualdisease (MRD) [7-9]. Universal application of MRDassays would be highly desirable, but so far progresstowards it has been slow because of the complexity andhigh costs of MRD evaluation [10]. So far, it has beenshown that the morphologic detection of leukemic cellsin day-15 or day-33 in bone marrow is prognosticallyimportant [3]. The rationale for the use of this strategybased on flow cytometry with normal immatureCD19+ cells (ie, those expressing CD10 and/or CD34)is the interesting option for bone marrow samples collectedfrom children with ALL after beginning of remissioninduction chemotherapy, because of theirexquisite sensitivity to glucocorticoids and other antileukemicdrugs. We therefore tested the possibility ofdisappearance of leukemic markers within 3 days ofprednisolone in vitro therapy. We have found that inmost cases, this short-term prednisolone therapy significantlyreduces the leukemic load both in precursor-B-lineage and T-lineage pediatric ALL. This was alsoobserved in tested leukemic lymphoid cell lines. Thisapproach might be useful to identify patients who arehighly sensitive to remission induction therapy [2] andalso those who are susceptible to the presence of MRD.We suggest that the simplified flow cytometric assaydescribed here would provide the valuable information.CONCLUSIONS1. Short-term in vitro therapy of leukemic cells withprednisolone is sufficient to induce downregulationof leukemic immunophenotype in patientsamples. This strategy was not effective in leukemicand lymphoid cell lines.2. Flow cytometry might be an important method inanalysis of minimal residual disease in pediatricacute lymphoblastic leukemia.ACKNOWLEDGEMENTSThe authors thank Beata Kolodziej, Beata Rafinskaand Malgorzata Kubicka for their technical support.REFERENCES1. Pui C.H., Relling M.V., Downing J.R.: Acute lymphoblasticleukemia. N. Engl. J. Med. 2004;350:1535-1548.2. Holleman A., Cheok M.H., den Boer M.L. et al.: Geneexpressionpatterns in drug-resistant acute lymphoblasticleukemia cells and response to treatment. N. Engl. J.Med. 2004; 351:533-542.3. Schrappe M., Reiter A., Ludwig W.D. et al.: Improvedoutcome in childhood acute lymphoblastic leukemia despitereduced use of anthracyclines and cranial radiotherapy:results of trial ALL-BFM 90. German-Austrian-Swiss ALL-BFM Study Group. Blood 2000;95:3310-3322.4. Riehm H., Feickert H.J., Schrappe M. et al.: Therapyresults in five ALL-BFM studies since 1970: implicationsof risk factors for prognosis. Hamatol. Bluttransfus.1987;30:139-146.5. Schrappe M., Camitta B., Pui C.H. et al.: Long-termresults of large prospective trials in childhood acute lymphoblasticleukemia. Leukemia 2000;14:2193-2194.6. http://www.ecacc.org.uk. The European Collection ofCell Cultures S, Wiltshire, UK.7. Szczepanski T., van der Velden V.H., van Dongen J.J.:Flow-cytometric immunophenotyping of normal and malignantlymphocytes. Clin. Chem. Lab. Med. 2006;44:775-796.8. Pui C.H., Boyett J.M., Rivera G.K. et al.: Long-termresults of Total Therapy studies 11, 12 and 13A forchildhood acute lymphoblastic leukemia at St. Jude Children'sResearch Hospital. Leukemia 2000;14:2286-2294.9. Lugthart S., Cheok M.H., den Boer M.L. et al.: Identificationof genes associated with chemotherapy crossresistanceand treatment response in childhood acute lymphoblasticleukemia. Cancer Cell 2005;7:375-386.10. Szczepanski T., Orfao A., van der Velden V.H. et al.:Minimal residual disease in leukaemia patients. LancetOncol. 2001;2:409-417.Address for correspondence:Jan Styczyński, MD, PhD,Department of Pediatric Hematology and OncologyNicolaus Copernicus UniversityCollegium Medicum in Bydgoszczul. Curie-Sklodowskiej 985-094 BydgoszczPolande-mail: jstyczynski@cm.umk.pltel: +48 52 585 4860fax: +48 52 585 4867Received: 25.11.2008Accepted for publication: 16.12.2008