Do infections facilitate the emergence of systemic sclerosis?

Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular obliteration, excessive extracellular matrix deposition, and fibrosis of the connective tissues of the skin, lungs, gastrointestinal tract, heart, and kidneys. Infections are believed to play a role in the immunopathogenesis of SSc. A number of infectious agents have been proposed as possible triggering factors in SSc. Homology between viruses and autoantibody targets suggests that molecular mimicry may play a role in the initiation of antibody response in disorders characterized by diffuse vascular disease, mainly SSc. Four pathogenic hypotheses have been proposed: molecular mimicry, endothelial cell damage, super-antigens, and microchimerism. Although several studies have provided important information linking infectious agents to SSc, a clear, direct association is still missing. It is very likely that the infectious agents are cofactors in a specific hormonal and environmental setting that mounts an immune reaction, which leads to the emergence of the disorder.