Interleukin-11 as an osteoprotegerin-inducing factor in culture medium of blastic cells from a patient with acute megakaryocytic leukemia complicated with osteosclerosis

We came across a rare case of acute megakaryocytic leukemia, the clinical course of which was relatively chronic and nonaggressive. This case was complicated with generalized severe osteosclerosis (OS). The medium in which blastic cells from the patient were cultured showed a strong activity to enhance the expression of an osteosclerotic cytokine, osteoprotegerin (OPG), as revealed by real-time quantitative RT-PCR and Western blot analysis. The OPG-inducing activity of the culture medium was neutralized by the anti-interleukin-11 (IL-11) antibody. These results indicate that IL-11 produced by the blasts was a causative factor of the OS observed in this patient.