What is the role of mononuclear infiltration in the pathogenesis of CREST syndrome?

Updated: Oct 05, 2020
  • Author: Jeanie C Yoon, MD; Chief Editor: Dirk M Elston, MD  more...
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Mononuclear infiltration probably precedes fibrosis of tissues. Histologic specimens from patients with disease duration of less than 2 years show mononuclear infiltration near blood vessels and dermal appendages. While this inflammatory infiltrate can accompany fibrosis in tissues, it can also be present without fibrosis, suggesting that it is an early event in the pathogenesis of scleroderma.

CD4 lymphocytes predominate in the inflammatory infiltrate. Suppressor T cells are diminished in number. Macrophages are present in higher numbers, as are eosinophils, basophils, mast cells, and B cells. These cells secrete a variety of cytokines, the balance of which is important in the pathogenesis of fibrosis.

Several cytokines have been implicated in the development of fibrosis. Transforming growth factor-beta (TGF-beta) stimulates collagen synthesis, and plasma levels of this cytokine are elevated in scleroderma patients (both limited and diffuse scleroderma). Fibroblasts from the skin of scleroderma patients express increased amounts of mRNA for TGF-beta and secrete higher levels of TGF-beta. Furthermore, these fibroblasts are not as sensitive as normal fibroblasts to stimulation by exogenous TGF-beta, suggesting that they are already maximally stimulated. TGF-beta3 in particular has been suggested as having a major role in the pathogenesis of the calcinosis often seen in persons with systemic sclerosis. [18]

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