Clinical Features and Treatment Outcome of Children with Myeloid Antigen Positive Acute Lymphoblastic Leukemia

Kim, Young Won; Yang, Chang Hyun; Park, Song Hee; Lyu, Chul Joo; Kim, Kir Young

Abstract

Purposes: Leukemic cells from a significant number of children with acute lymphoblastic leukemia (ALL) express the protein antigens which present the characteristic of both lymphoid and myeloid cells. However the clinical significance of this immunophenotype has remained controversial. In this study, we have retrospectively determined the relationship between the myeloid antigen expression and the outcome after the treatment in the patients of newly diagnosed ALL.
METHODS
The total number of one hundred and one newly diagnosed childhood ALL patients, who were admitted to the Department of Pediatrics at Severance Hospital from January 1992 to December 1997 were studied. They were classified as the myeloid antigen positive (My Ag+) and myeloid antigen negative (My Ag-), according to the expression of CD13 and/or CD33 antigens on the surface of leukemic cells. Nineteen patients (19%) among them were myeloid antigen positive.
RESULTS
There was no difference between My Ag+ and My Ag- patients in favourable presenting features. The remission rate after induction therapy had no difference between My Ag+ and My Ag- patients. Most of all, there was no difference in 4-year event-free survival (EFS) in both groups. Four year-EFS of My Ag+ patients was 82.2% and that of My Ag- patients was 78.7% (P=0.9). The duration of mean survival rate of My Ag+ patients was 51.1 months and My Ag- patients was 67.8 months.
Conclusions
We concluded that there was no difference between MyAg+ ALL and MyAg- ALL patients in the outcome of its treatment. In contrast to previous studies, this result was independent of treatment risk category, demonstrating that myeloid antigen expression was not an adverse prognostic factor for childhood ALL.