OBJECTIVETo investigate the immunophenotypes of B cell acute lymphoblastic leukemia (B-ALL) in patients at different age and to explore its clinical application in prognosis prediction and individualized treatment.

METHODThe immunophenotyping in 329 patients with B-ALL at different ages was performed by CD45/SSC gate four-color fluorescence flow cytometry.

RESULTSIn all patients detected the highest incidence of lymphoid-associated antigens was CD19, HLA-DR, CyCD79a and cTdT, followed by CD10, CD22, CD34, CD38, CD20 and CyIg. B-ALL showed a higher concomitant expression rate of myeloid antigens CD13 and CD33; the CD11b, CD15, CD117 and T antigens (CD4, CD7 and CD56) were rarely expressed. CD10⁻ pro-B acute lymphoblastic leukemia (Pro - B-ALL) was predo-minant in infantile group (60%) with CD117 higher expression (40%). Subtype Pro-B-ALL was rarely expressed in childhood and adolescent group, but the incidence of disease increased as the age increase, the incidence of youth group (22.7%) and middle-aged' group (14.8%) were significantly higher than childhood group (4.4%). The influence of age on immunophenotypic characteristics of the adult B-ALL was not significant, the heterogeneity of antigen expression was less in the adult patients at different ages. The expression of CD10 and CD38 was lower, while expression of CD34, CD13 and CD33 were higher in adult patients than those in children patients. There was no significant difference in incidence of precursor-B-ALL (Pre-B-ALL) among different age groups (P > 0.05), but its incidence increased along with age increasing, and the expression of CD20 was higher in Pre - B-ALL than that in Pro - B-ALL and common B-ALL.

CONCLUSIONThe immunophenotype characteristics of B-ALL in the patients at different ages is of great value in prediction for disease prognosis and guidence of individualized treatment.