Background: CD133 antigen is expressed restrictively in the immaturesubset of the CD34+ cellshence; it is expected to be a valuableprognostic marker in acute leukemia.
Aim of the work:The present study aimed to assess CD133 expression frequency in patients with acute leukemia and to evaluate its relation to disease outcome.
Patients and methods: The present study was carried on seventy-five newly diagnosed acute leukemia patients, recruited from hematology/oncology clinic of National Cancer Institute.The patients were divided into two groups,24 acute lymphoblastic leukemia (ALL) and 51 acute myeloblastic leukemia (AML) patients.Patients were followed up through out the period of the study (12 months). All patients were subjected to the complete history taking, through clinical examinationandlaboratory investigations, including complete blood count (CBC), Bone marrow (BM) aspirateexamination, Immunophenotyping and assessment of CD133 expression for peripheral or BM samples using EPICS XL Coulter Flow Cytometer.
Results:In this study CD133 was expressed in 28 patients from 75 patients with acute leukemia (37.3%), 21 patients with AML from 51 (41.17%) and 7 patients with ALL from 24 (29.16%). Theexpression of CD133 was higher in AML than ALL without statistical significance (20.41±19.28vs15.2±14.69;p = 0.34).No significant correlation was found between CD133+veexpression and the clinical data as regardsex,age, hepatomegaly, splenomegaly and lymphadenopathy in both ALL and AML. No significant correlation was found between CD133+ve expression and the hematological data as regard, WBCs, Hb, platelets and peripheral blasts in both ALL and AML. There was significant negative correlation between CD133 and BM blasts in ALL, but insignificant in AML (r = -0.45; p = 0.02 vsr= -0.04;p= 0.78).In both ALL and AML,Patients with CD133+ve expression had statistically significant poor clinical outcome (relapse or death) more than patients with CD133-ve expression( ALL, p = 0.012, AML, p = 0.021). Patients with CD133+ve expression had shorter overall survival time compared with CD133-ve and this wassignificant in AML and insignificant in ALL, (8.95±0.69 monthsvs10.3±0.54 months, p = 0.05),(9.16±0.77months vs10.6±0.1.67 months, p= 0.3).
Conclusion:CD133-positive expression is an independent poor prognostic factor in adult acute leukemia and its expression could characterize a group of acute leukemic patients with resistance to standard chemotherapy, as well as high incidence of relapse and death.