Systemic sclerosis I(cleroderma) is a connective tissue disease caracterized by an aberrant immune activation, a vasculopathy and a fibrosis of skin and multiple internal organs (lung, kidneys, gut, among others). At present no unifying pathogenetic hypothesis exists to explain all aspects of this disease. The current hypothesis is that in patients with a favourable genetic background, certain environmental factors could produce alterations of cellular and humoral immunity and alterations of the microcirculation resulting in excessive fibrosis. A crucial component in systemic sclerosis pathogenesis is the persistent and unregulated activation of genes encoding the various extracellular matrix proteins. This is in correlation with different cytokines and growth factors produced mainly by T lymphocytes.