Prognostic Value of CD45 Surface Antigen in Children with Acute Lymphoblastic Leukemia Treated according to Total XV Protocol

Abstract

Background: Acute Lymphoblastic Leukemia (ALL) is a malignant disease of the bone marrow in which early lymphoid precursors proliferate and replace the normal hematopoietic cells of the marrow. Further improvement of outcome in childhood acute lymphoblastic leukemia could be achieved by identifying additional high-risk patients who may benefit from intensified treatment. CD45 cell surface antigen is a transmembrane protein with tyrosine phosphatase activity, expressed by all nucleated cells of hematopoietic origin, except erythrocytes and platelets. Aim of Study: To assess the prognostic value of CD45 surface antigen in children with acute lymphoblastic leukemia who treated according to TOTAL XV protocol. Subjects and Methods: This study was conducted on 25 patients with acute lymphoblastic leukemia who treated according to Total XV protocol. CD45 expression was measured by flowcytometry and cutoff value for CD45 expression is set on 90% to distinguish a CD45-high from a CD45-low group. Results: There was significant correlation between CD45 expression and age. There was no statistically significant differences between low and high CD45 groups as regard initial total leucocytic count, bone marrow blast cells percentage, leukemic phenotype, DNA index, t (9, 22) or CNS status. There was statistically significant difference between the two groups regarding early treatment response, risk stratification, incidence of relapse and event free survival. Conclusion: Measuring the intensity of expression of CD45 surface antigen has a prognostic value in childhood acute lymphoblastic leukemia. So consideration of CD45 expression may serve as an additional stratification tool. Recommendations: Multicenter study on large number of patients with follow-up for longer duration is recommended to prove the prognostic value of CD45 expression in childhood acute lymphoblastic leukemia.