Interleukin-6 plasma levels and tumor size in cardiac myxoma

Abstract

In a certain subset of patients with cardiac myxoma noncardiac, constitutional signs and symptoms that resemble autoimmune disease are observed, such as hypergammaglobulinemia, fever, autoantibodies, and elevated erythrocyte sedimentation rate (ESR) and white blood cell count. The conditions that determine whether a patient becomes affected by these constitutional signs and symptoms are unknown. Interleukin-6 (IL-6), a multifunctional immunoregulatory cytokine that is involved in B-cell differentiation, T-cell activation, acute phase response, and hematopoiesis, has b e e n found in these patients, a In view of the pleiotropic nature of IL-6 and of cytokines in general we wanted to know whether there are further revealing markers that can be linked to the immunologic features of cardiac myxoma. We studied six patients with nonfamilial cardiac myxoma (ages 44 to 65 years; 1 man, 5 women). Diagnosis was established echocardiographically and confirmed histologically. None of the patients had evidence of systemic infection. Endotoxin levels were measured to rule out asymptomatic infection. All patients gave their informed consent. We analyzed preoperative plasma samples for IL-1/3, IL-1 receptor antagonist (IL-lra), IL-2, soluble IL-2 receptor (slL-2r), IL-6, soluble IL-6 receptor (sIL-6r), IL-8, tumor necrosis factor-alpha (TNF-c0, TNF receptor I (TNF-rI) and I! (TNF-rII), and granulocyte macrophage colony-stimulating factor with commercially available enzyme-linked immunosorbent assay kits (Quantikine, R & D Systems, Minneapolis, Minn.). Endotoxin levels were determined with a modified chromogenic limulus amebocyte lysate test (Chromogenix, M61ndal, Sweden). The normal range of the mediator levels was provided by the manufacturer. It is noteworthy that TNF-c~ values may give false-negative results because of the short half-life of this mediator. Patient data and results are listed in Table I. Patients 1 through 4 did not have constitutional symptoms. Patient 1,