EFFECTS OF AN ANTI-INTERLEUKIN-6 (IL-6) MURINE MONOCLONAL-ANTIBODY INA PATIENT WITH ACUTE MONOBLASTIC LEUKEMIA

Because IL-6 has been involved in the pathogenesis of acute monoblasti c leukemia, we investigated the in vitro and-proliferative effect and the in vivo and-tumoral effect of an and-IL-6 murine monoclonal antibo dy (mAb) in a patient with M5B type acute leukemia. In the current stu dy, we clearly show the IL-6 dependence of monoblastic cell viability and proliferation in vitro in short-term cultures of malignant cells a nd the clinical activity of the anti-IL-6 murine mAb. The complete neu tralization of IL-6 in vivo was associated with a transient but comple te disappearance of malignant monoblastic cells in the peripheral bloo d, with improvement or even normalization of several other biological parameters of disease activity. No immunization against the anti-IL-6 murine mAb was observed.