Autoimmune markers are undetectable in end stage idiopathic dilated cardiomyopathy

Background-Autoreactive humoral and cellular immune responses may be involv ed in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Certain human leucocyte antigens (HLA) could also be linked to the development of I DC. Aim-To determine whether various markers of autoimmunity are present in the final phase of the disease, to substantiate the role of an autoimmune proc ess in IDC. Methods-37 patients with end stage IDC were studied, together with 39 patie nts with end stage heart disease of known aetiology who were included for c omparison. Multiple myocardial tissue samples from the explanted heart of e ach patient were evaluated (immuno) histologically. An indirect immunofluor escence assay was used to screen patient serum samples for the presence of heart specific autoantibodies. HLA class I and II frequencies were determin ed in each group and compared with HLA frequencies from healthy blood donor s. Results-Only scanty small mononuclear cell infiltrates were present in myoc ardial tissue of seven patients with IDC and of 11 patients with heart dise ase of known cause. The majority of these inflammatory cells were negative for T cell markers. All blood specimens were negative for heart specific au toantibodies and there was no apparent association of IDC with particular H LA phenotypes. Conclusions-These findings suggest that an active autoimmune process is not involved in the end stage of IDC.