Autoimmune diseases and peptide variations.

The immune system plays an essential role in the defense of the host against invaders. Enormous numbers of lymphocytes are recruited and immense numbers of antibodies or cytokines are secreted in various kinds of immune response. But the system also has the possibility of being the cause of tissue injury or some kind of diseases. For example, when their functions target their host, an autoimmune disease occurs. Although the pathogenesis of various autoimmune diseases has been scrutinized intensively, there is little evidence as of yet. But it has been reported that in most of the disease subjects, a broad spectrum of antibodies recognizing components of self tissue or circulating self antigens that normally should be ignored are observed. In this study, we come to the conclusion that proteins targeted by these autoreactive antibodies share the same peptides with some kind of proteins of viruses known to infect human. This result supports the fact that viral infection is a speculative cause of the disease in some subjects.