Immunohistochemical expression of transforming growth factor β3 in calcinosis in a patient with systemic sclerosis and CREST syndrome

Sir, Systemic sclerosis (SSc) is characterized by extensive generalized fibrotic destruction associated with increased accumulation of the extracellular matrix (ECM) in the skin and other involved organs.1 Calcification of the skin may occur in all forms of SSc, but is most commonly seen as part of CREST syndrome. Calcinosis generally results from dystrophic calcification associated with massive collagen degeneration. However, the pathogenesis of calcinosis is not well understood. Transforming growth factor β (TGF β) is known to play an important role in the regulation of the ECM in dermis metabolism and in increasing collagen production by fibroblasts.2 TGF β may also play a critical role in SSc and is considered to be one of the potential contributors to the development of SSc.3 The most compelling evidence implicating TGF β in the pathogenesis of fibrosis in SSc is provided by in situ studies. Three isoforms of TGF β have been identified in mammals. Abnormal expression of TGF β was first demonstrated in involved SSc skin by immunohistochemical methods. Helman et al.4 found that the TGF β1 protein peaked in progressive skin involvement, TGF β2 peaked in clinically uninvolved skin and TGF β3 peaked in skin with early involvement.