DIFFERENTIAL CHEMOSENSITIVITY IN A CHILD WITH CONGENITAL RELAPSING ACUTE LYMPHOBLASTIC LEUKEMIA

Abstract

Described is a case of a boy with congenital acute lymphoblastic leukemia (ALL) with pre-pre-B-ALL immunophenotype, presenting as diarrhea, organomegaly, hyperleucocytosis of 1434 G/L, and tumorlysis syndrome. The lymphoblasts showed low proliferative activity and high in vitro drug sensitivity measured by the MTT assay. An excellent response to therapy was observed, but relapse occurred 3 months later. On relapse, blasts showed extremely high drug resistance, high expression of P-glycoprotein, and high proliferative activity. The response to therapy was again positive, but a second relapse occurred in 1 month. The MTT assay indicated increasing drug resistance to all drugs. Cytogenetic analysis revealed deletion in 11q23 locus. This unfavorable case shows complex biology and differential drug resistance in congenital leukemia.

• Drug Resistance
• Mll Locus
• P-GLYCOPROTEIN
• Tailored Therapy