Comparison of cellular drug resistance in acute lymphoblastic leukemia in children and in adults

The prognosis of acute lymphoblastic leukemia (ALL) in adults is poor in comparison to children with ALL. The aim of the study was to determine the drug resistance profile in lymphoblasts of adult ALL in comparison to paediatric ALL. Drug resistance profile was compared by means of the MTT assay in 10 adults and 11 children samples at initial presentation of ALL. The following 14 drugs were tested: cytosine arabinoside, L- asparaginase, dexamethasone, daunorubicin, doxorubicin, idarubicin, 4-HOO-ifosfamide, 6-mercaptopurine, mitoxantrone, prednisolone, teniposide, 6-thioguanine, vincristine and vepesid. Lymphoblasts from adult patients were more resistant to all tested drugs. For idarubicine, L-asparaginase and teniposide the results reached statistical difference. The resistance ratio of adult vs children ALL was the most prominent for L-asparaginase (43-fold), prednisolon (> 15.7-fold), teniposide (12-fold), vincristine (9,3-fold), daunorubicin (5,4-fold) and cytosine arabinoside (5,3-fold). The resistance profile expressed by combined resistance to prednisolon, vincristine and L- asparaginase (PVA score) may be a fundamental difference between adult and children ALL which may underlie its different biological aspects and explain the difference in prognosis.