This disclosure provides a method for treating a pediatric subject afflicted with acute B cell precursor leukemia (BCP-ALL) comprising administering to the subject an anti-killer cell immunoglobulin-like receptor (KIR) antibody or an antigen-binding portion thereof that binds specifically to an inhibitory KIR and blocks inhibitory KIR activity, thereby potentiating NK cell lytic activity. An exemplary anti-KIR antibody for use in this method is lirilumab. The disclosure also provides a kit for treating a subject afflicted with pediatric BCP-ALL, the kit comprising a dosage ranging from 0.01 to 20 mg/kg body weight of an anti-KIR antibody or an antigen-binding portion thereof that specifically binds to an inhibitory KIR and blocks inhibitory KIR activity, and instructions for using the anti-KIR antibody or an antigen-binding portion thereof in any of the disclosed methods for treating pediatric BCP-ALL.