Dilated (Congestive) Cardiomyopathy—The evidence for and Against a Disorder of Cellular Immunity and Infection

The cause of congestive cardiomyopathy is unknown but it has been postulated that it may be triggered by a virus infection and perpetuated by an immunological mechanism1–3. There has been a considerable accumulation of data concerning possible humoral mechanisms in the aetiology of congestive cardiomyopathy, and the body of evidence to date suggests that antiheart antibodies are present in congestive cardiomyopathy. Unfortunately, the relevance and true incidence of antiheart antibodies has been obscured by confused terminology and poor trial design. Many studies have not been performed in a blind manner4–7, and some did not have control groups8, or used the same control group for different studies while continuing to test more cardiomyopathic patients9,10. These studies have given rise to the erroneous impression that antiheart antibodies may have a significant aetiological role in congestive cardiomyopathy. However, studies performed with blinded, independent observers and repeated observations11–14 have not corroborated this impression, and to date there is no evidence to suggest that antiheart antibodies are anything more than non-specific findings in heart disease whatever the underlying abnormality. Work attempting to clarify the role of cellular immune mechanisms in congestive cardiomyopathy may be open to similar errors.