IN VITRO DRUG RESISTANCE IN CHILDHOOD MATURE B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA

Abstract

B a c k g r o u n d . Mature B-cell acute lymphoblastic leukemia (B-ALL) is a rare type of leukemia in children and counts for 1-2% of all leukemia cases. Pediatric B-ALL is treated according to protocols for non-Hodgkin lymphomas. O b j e c t i v e . The aim of the study was to analyze the in vitro drug resistance in children with B-ALL compared to ALL with other phenotypes. M a t e r i a l a n d m e t h o d s . A total number of 15 children with B-ALL (6 girls and 9 boys, median age 8 years, range 1.9-15 years) were included into the analysis. The in vitro drug resistance tests on leukemic cells were performed by means of the MTT assay. The results of B-ALL patients were compared to those obtained in patients with pre- B/common ALL (479 cases), pro-B-ALL (31cases) and T-ALL (87 cases). Results: B-ALL cells were more resistant than pre-B/common-ALL cells to dexamethasone and idarubicin. In comparison to pro-B-ALL phenotype, B-ALL blasts were more resistant to idarubicin and more sensitive to treosulfan. No significant differences were found in the in vitro drug resistance between B-ALL and T-ALL. Blasts of T-ALL were more resistant than pre-B/common-ALL cells to most of tested drugs. Conclusion: From the clinical point of view, B-ALL cells have similar in vitro drug sensitivity when compared to T-ALL, and higher drug resistance to dexamethasone than pre-B/common-ALL.