Abstract
BACKGROUND: Macrophage accumulation found in biopsy specimens of patients with dilated cardiomyopathy (DCM) has been thought to reflect chronic myocarditis. However, it is unsettled whether they are responsible for the active or persistent phase of the disease. OBJECTIVE: The aim of this study was to count the number of macrophages in relation to plasma concentrations of cardiac troponin T (cTnT). METHODS: We studied the biopsies of 181 patients with DCM by immunohistochemistry using anti-CD68(+) antibodies. The total number of CD68(+) and the number of CD68(+) cells attached to injured cardiomyocytes were counted and presented as the number of cells/mm(2). RESULTS: Two expression patterns of CD68(+) macrophages were observed: those localized freely in the interstitial space only, and the cells attached to injured cardiomyocytes. As regards macrophages adhered to injured cardiomyocytes, 72 out of 181 (39.8%) patients presented these cells in the biopsy sections. Both the total number of CD68(+) macrophages and the number of CD68(+) cells directly adhered correlated negatively with cTnT in the serum of DCM patients (Spearman's rho, r = -0.45, P < 0.001 and r = -0.31, P = 0.009, respectively). CONCLUSION: Macrophages attached to injured cardiomyocytes may reflect chronic (ongoing) inflammation in the myocardium.