Prognostic role of myocardial tumor necrosis factor-alpha and terminal complement complex expression in patients with dilated cardiomyopathy

Background: In patients with dilated cardiomyopathy (DCM), elevated plasma levels of tumor necrosis factor-α (TNF-α) are associated with poor prognosis. The terminal complement complex (C5b-9) stimulates myocardial TNF-α expression. Aims: To investigate whether myocardial TNF-α and C5b-9 expression correlate with clinical outcome in DCM. Methods and results: 71 patients with DCM underwent myocardial biopsy. Biopsies were analyzed for TNF-α, C5b-9, markers of inflammation and for viral genome. Patients were divided into three groups according to biopsy results: group A: no TNF-α and no C5b-9; group B: TNF-α or C5b-9; and group C: TNF-α and C5b-9. NYHA classification, ECG and echocardiography were documented. Patients received conventional treatment of heart failure and, in a few cases, additional treatment with interferon β_1b (virus positive) or prednisolone (inflammatory DCM). There were 13 patients (18%) in group A, 19 patients (27%) in group B, and 39 patients (55%) in group C. All groups had a similar and significant improvement in NYHA classification and echocardiographic parameters. TNF-α and C5b-9 did not significantly correlate with the presence of viral genome or with markers of inflammation. Conclusion: TNF-α and C5b-9 are widely distributed in the myocardium of DCM patients. Neither of the antigens correlates with clinical outcome. Myocardial TNF-α may not be a useful prognostic marker in DCM.