Markers of disease activity in systemic sclerosis.

T he cause of systemic sclerosis (SSc) is still unknown. In the last decade several key events in the pathogenesis have been suggested,’ including the endothelial injury, the fibroblast activation, and the peculiar immunologic involvement.’ The disease starts in the microvascular system, spreading to the connective tissue. * The process involves endothelial cells (EC), lymphocytes, and fibroblasts.‘,* On clinical examination, physicians are unable to identify the phase of the disease, that is, the level of EC injury and/or fibroblast activation. The evaluation of serologic markers of disease activity, showing the involvement of the endothelial, fibroblast, and immune systems, are therefore, useful tools for the clinical and therapeutic approaches to SSc. The aim of this chapter is to review the markers that may help clinicians determine SSc evolution and assess the disease.