Prognostic value of myeloid antigens expression in childhood acute lymphoblastic leukemia

BACKGROUND: Leukemic blasts in acute lymphoblastic leukemia (ALL) may have immunological features of both lymphoid and myeloid lineages known as aberrant myeloid antigens expression in ALL, which are explained as abnormal genetic program of leukemic cells that lead to lineage infidelity. In this study, CD13, CD14, and CD33 (which are the most frequent myeloid antigens associated with aberrant antigens expression in ALL) were investigated. OBJECTIVES: To evaluate the occurrence of aberrant myeloid antigens expression in childhood ALL and its effects on complete remission and other parameters. MATERIALS AND METHODS: This study was conducted on 31 pediatric patients with newly diagnosed de novo ALL (27 B-ALL, 4 T-ALL) in Children Welfare Teaching Hospital/Medical City of Baghdad; diagnosis of ALL based on morphology and cytochemistry, CD13, CD14, CD33 were investigated as myeloid antigens using four-color flow cytometry. RESULTS: Five cases of ALL (16.13%) out of 31 cases were confirmed to have aberrant myeloid antigens expression (CD13 was expressed in all five cases, CD33 was expressed in three cases, and CD14 was not expressed in any of these five cases). Complete remission was achieved in 90.30% (28 patients) and all cases with aberrant myeloid antigens expression achieved complete remission; however, despite this, there was no significant difference in complete remission between myeloid-positive (MY+) and myeloid-negative (MY−) cases, P > 0.05. Regarding other parameters, there were significant statistical differences in lactate dehydrogenase (LDH), hemoglobin value, and bone marrow (B.M.) blasts percent at diagnosis between MY+ and MY− cases, P < 0.05; however, there was no significant differences in leukocytes count, platelets count, peripheral blood blast percent at diagnosis, age, and gender, P > 0.05. CONCLUSIONS: The most frequent aberrant myeloid antigens expression in childhood ALL is CD13 and less frequently is CD33 while CD14 showed no expression; myeloid antigens expression in ALL may have better prognosis as they have lower B.M. blast percent and LDH value.