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Aims The aim of this study was to characterize the up-regulation of major histocompatibility complex antigens class I (HLA-A, B, C) and class II (HLA-DR), and inter-cellular adhesion molecule-1 with special emphasis on de novo induction of these molecules on cardiac myocytes in patients with suspected myocarditis.Methods Endomyocardial biopsy specimens were obtained from 83 consecutive patients. Specimens were subdivided into two groups according to clinical presentation of the disease: Group A, 58 patients with idiopathic congestive heart failure and Group B, 25 patients without heart failure. In group A, 15% of patients had active myocarditis, 36% had borderline and 48% no myocarditis according to Dallas criteria. In group B, myocarditis distribution was 12%, 36% and 52%, respectively. The major histocompatibility complex was considered to be positive when the immunoreactivity index was ≥3+; intercellular adhesion molecules were considered positive when the score was ≥2+.Results We observed two characteristic staining patterns of the HLA molecules on cardiac myocytes: (i) multifocal sarcolemmal staining at the sites of mononuclear inflam-matory infiltration, (ii) linear sarcolemmal staining with otherwise normal endomyocardium. Positive immunoreactivity was observed in 60% of patients in group A, and in 44% of patients in group B. We found no correlation between a histopathological diagnosis of myocarditis or left ventricular systolic function and positive immunoreactivity.Conclusion The lack of correlation between immuno-histological signs of active inflammation and clinical symptoms in patients with myocarditis may indicate independence of an immunological mechanism. The lack of correlation between immunoreactivity and histopathological diagnosis of myocarditis may suggest low sensitivity of traditional histological evaluation. In our opinion, the induction of major histocompatibility and intercellular adhesion molecules on cardiac myocytes may indicate an autoimmune inflammatory response in patients with inflammatory myocardial disease. Immunohisto-chemical methods may be helpful in selecting patients for immunosuppressive therapy. [ABSTRACT FROM PUBLISHER]

Oral antiplatelet drugs are a cornerstone of modern pharmacotherapy in cardiovascular atherothrombotic diseases. The efficacy of acetylsalicylic acid (ASA, aspirin) and clopidogrel in decreasing the risk of adverse events in coronary heart disease patients has been well established in the past 20 years. Despite chronic oral antiplatelet therapy, a number of atherothombotic events continue to occur. In recent years, a number of reports in the literature have shown possible relationships between residual platelet activity, as measured with a variety of laboratory tests, and clinical outcome, raising the possibility that 'resistance' to oral antiplatelet drugs may underlie many such clinical adverse events. The present position paper, conveyed within a group of clinical cardiologists with expertise in thrombosis appointed by the Section of Cardiovascular Interventions of the Polish Cardiac Society, has been further elaborated and endorsed by the Working Group on Thrombosis of the European Society of Cardiology. It aims at summarizing the main findings in this complex area, issuing opinions in cases of high controversy, and fostering future research in this area to obtain reliable laboratory and clinical data for the resolution of the many problems still open.