Background: Aberrant myeloid antigen (MA) co-expression and high expression of CD34 antigen on the blasts of acute lymphoblastic leukemia (ALL) patients are independently reported to have a role in pathogenesis and prognosis. This study was conducted to determine whether these two parameters are related.
Methods: A total of 204 cases of ALL were included in an analysis of blast immunophenotypic data. CD34 expression was categorized as low when less than 50% of blasts were CD34-positive (CD34(low)) and as high when 50% or more were CD34-positive (CD34(high)).
Results: Of 204 cases of ALL, 163 and 41 were of B-cell origin (B-ALL) and T-cell origin (T-ALL), respectively. Of all cases, 132 (64.7%) showed co-expression of MA and among these, 101 (76.51%) were CD34(high), while the remaining 31 (23.48%) were CD34(low). Of 72 cases without MA co-expression, 25 (34.72%) were CD34(high) and 47 (67.25%) were CD34(low). Furthermore, of 163 cases of B-ALL, 111 showed co-expression of MA and 84 of these were CD34(high). Of 52 cases of B-ALL without MA expression, 22 were CD34(high). Among 41 cases of T-ALL, 21 co-expressed MA, 17 of which were CD34(high). Moreover, all 20 cases of T-ALL without co-expression of MA were CD34(low). These differences were statistically significant.
Conclusion: We observed a strong correlation between aberrant MA expression and CD34(high) expression on the blasts of ALL. We hypothesize that these different patient subsets may represent unique prognostic characteristics.
Keywords: Aberrant myeloid antigen co-expression; Acute lymphoblastic leukemia; CD34; Flow cytometry; Immunophenotyping.