Tumour necrosis factor-α expression in idiopathic dilated cardiomyopathy:: Correlation to myocardial inflammatory activity

High numbers of inflammatory cells are found in a subgroup of patients with idiopathic dilated cardiomyopathy. (IDCM), We hypothesized that the extent of inflammation is linked to myocardial TNF-alpha expression in human IDCM, Fourteen patients who consecutively underwent endomyocardial biopsy (EMB) were stratified into two groups-a group with low and a group with high myocardial inflammatory index (MII)-based on immunohistochemical analysis of cellular infiltration and HLA I and II expression. Myocardial TNF-alpha messenger RNA (mRNA) expression was determined by reverse transcriptase polymerase chain reaction, TNF-alpha protein was localized by immunohistochemistry and TNF-alpha serum levels were measured by EIA, IDCM patients with a high MII(n=6) showed a 1.9-fold higher TNF-alpha mRNA expression when compared to IDCM patients with low MII (n=8, P=0.020), TNF-alpha protein was detected at perinuclear regions of cardiac myocytes and the endothelium. TNF-alpha serum levels were 3.0 (0.55) pg/ml in patients with high MII compared to 1.35 (0.20) pg/ml in patients with low MII (P=0.017), According to immunolocalization cardiac myocytes and the endothelium seem to be the major source of TNF-alpha production, Whether the elevated systemic level of TNF-alpha found in patients with high MII are elaborated by the myocardium or are produced by other tissues representing a general immune activation is not clear. (C) 2000 Academic Press.