THE ROLE OF IMMUNOPHENOTYPE IN ACUTE LYMPHOBLASTIC-LEUKEMIA OF INFANTAGE

The prognosis of acute lymphoblastic leukemia in infants is still sign ificantly worse than that of older children. This is thought to be due to both clinical and biological factors, such as high white blood cel l (WBC) counts at diagnosis, irregular or immature phenotypes, and mol ecular and cytogenetical abnormalities. In order to focus the signific ance of immuno-phenotypic analysis, we have reviewed the immunophenoty pic studies of 145 infants under 18 months of age treated at the AIEOP centers from 1984 to 1992. Children have been divided in three age gr oups of six months each; WBC count at diagnosis has been evaluated bot h as mean values and within different categories (<10.10(9)/L, >50.10( 9)/L, >100.10(9)/L). These have been studied in correlation with immun ophenotype and with the expression of single, specific markers. A sign ificant correlation has been found between young age, high WBC count a nd immature phenotypes. Common ALL was more frequent in older children and showed lower WBC counts. Moreover, event-free survival was signif icantly better in older children with WBC count <100.00/mm(3), with CD 10+, MyAg- ALL. Therefore, we suggest that immunophenotypic analysis i s still an important prognostic factor and can be usefully used, toget her with simple clinical data, to plan therapy for ALL in infants.