The role of interleukin-4 in the negative regulation of leukemia cell growth.

Interleukin-4 (IL-4), originally identified as a B-cell growth factor, has been shown to inhibit certain stages of hematopoietic stem cells. Recently, IL-4 has been recognized as a negative regulatory factor in the growth of hematologic malignancy. In myeloid leukemias, IL-4 can suppress the growth of growth factor-dependent leukemic blast cells derived from acute myelogenous leukemia (AML). IL-4 also suppresses the growth of chronic myelomonocytic leukemia cells through inhibiting the "autocrine" production of IL-6 or granulocyte/macrophage colony-stimulating factor. In lymphoid malignancies, IL-4 can inhibit the proliferation of neoplastic cells from Ph1-positive acute lymphoblastic leukemia, non-Hodgkin's B-cell lymphoma, and multiple myeloma. Thus, IL-4 is expected to be useful as a therapeutic agent for these hematologic malignancies.