The same HLA-DQ alleles determine either susceptibility or resistance to different coxsackievirus-mediated autoimmune diseases

An important characteristic of autoimmune diseases is their association wit h major histocompatibility complex class I and class II alleles. In this st udy, we compared insulin-dependent diabetes mellitus (IDDM) with idiopathic dilated cardiomyopathy (IDC) from a strictly immunologic perspective. Alth ough the target organs are different, being in one case the insulin-produci ng beta cells of the pancreas and in the other case the myocytes of the hea rt, many aspects of the tissue-specific immune destruction are common. Simi lar yet different Coxsackievirus B strains with either pancreotropic or car diotropic specificity are able to perpetrate the first injury of the respec tive target tissue. Their shared capacity of inducing a superantigenic reac tion further enhances the damage. Once previously secluded autoantigens are then exposed to the immune system, the tissue injury is completed via a mo re conventional type of immune response. On the basis of the compounded res ults we obtained, it is possible to propose that the same HLA-DQ molecules which are able to protect the individuals from IDDM (e.g., HLA-DQA1*0102, D QB1*0602) seem to favour the enteroviral attack to the myocardium, while al leles which confer the strongest susceptibility to IDDM (e.g., DQA1*0301, D QB1*0302), seem unable to sustain the immune attack against the heart.