OBJECTIVE: To study the expression levels of interleukin-8 (IL-8) and its receptor in bone marrow cells of children with acute leukemia. METHODS: The expressions of IL-8 and its receptor in bone marrow cells were detected using RT-PCR in 22 cases of acute lymphoblastic leukemia (ALL) and 10 cases of acute myelocytic leukemia (AML). RESULTS: In 5 of 10 AML patients and in 13 of 22 ALL patients, the cells expressed IL-8 mRNA. In 4 AML cases and in 9 ALL cases, the cells expressed IL-8 receptor mRNA. The IL-8 expression levels in AML patients were significantly higher than those in ALL patients(P<0.05). The cells from patients with M_4-M_5 AML expressed a higher IL-8 mRNA level than those from M_2-M_3 AML patients(P<0.05). Of the ALL children, the IL-8 expression levels in B-ALL children were significantly higher than those of T-ALL children(P<0.05). After induction chemotherapy, the expression levels of IL-8 and its receptor in bone marrow cells of children with acute leukemia were significantly reduced(P<0.05). CONCLUSIONS: IL-8 and its receptor may be expressed in childhood acute leukemia. Children with M_4-M_5 AML or B-ALL can express a higher level of IL-8 mRNA in bone marrow cells. Induction chemotherapy can decrease the expression of IL-8 and its receptor.