Contribution of Monocytes to Overproduction of Interleukin-6 in a Case of Cardiac Myxoma

Cardiac myxoma cells have been demonstrated to produce interleukin (IL)-6, but its role in the systemic and immunologic manifestations of patients with this tumor is controversial. There is no evidence of any other source of such cytokine, but here we report a case of myxoma with systemic manifestations at diagnosis in which we evaluated the IL-6 production by peripheral blood cells before and after surgical tumor resection. Peripheral blood mononuclear cells were isolated by density gradient centrifugation, and the IL-6 expression in monocytes and lymphocytes was evaluated by flow cytometry. Before surgery, 74.4% of monocytes produced IL-6, but 1 month after surgery, a decrease in both the number of monocytes and the percentage of these cells expressing IL-6 was found along with an improvement of systemic and immunologic manifestations. Here, we demonstrated for the first time that monocytes contribute to the elevated production of IL-6 in patients with myxoma.