Mast cells, extracellular matrix components, TGF beta isoforms and TGF beta receptor expression in labial salivary glands in systemic sclerosis

Objective-To determine whether there was altered elaboration of noncollagen ous extracellular matrix proteins or expression of TGF beta isoforms and th eir receptors in salivary glands of patients with systemic sclerosis (SSc) and Raynaud's phenomenon (RP). Because of the possible role of mast cells i n the early stages of SSc their presence was also investigated. Methods-Sections of normal labial salivary glands (n=10) and glands from pa tients with SSc (n=13) and RP (n=5) were stained immunohistochemically and using acid toluidine blue. Results-SSc glands contained more mast cells than control tissues (p<0.005) and similar numbers to those found in RP specimens. There were no differen ces in the pattern or amount of non-collagenous matrix proteins detected. T enascin and elastin were predominantly found surrounding ducts whereas fibr onectin had a more general distribution. TGF beta isoforms and receptors we re expressed by glandular epithelium, fibroblasts, vascular endothelium and inflammatory cells. Cell counts showed no differences in expression of TGF beta 1 or TGF beta receptors between groups. However, the percentage of TG F beta 2 positive fibroblasts was significantly higher in SSc glands compar ed with controls (p<0.004). RP glands showed an intermediate level of expre ssion. By contrast, a lower percentage of RP fibrolasts expressed TGF beta 3 compared with controls with SSc glands showing an intermediate level of e xpression. Conclusions-These results show that (a) there are no changes in glandular e xpression of tenascin, elastin and fibronectin in SSc and RP and (b) both c onditions are associated with an increased salivary gland mast cell populat ion and changes in expression of TGF beta 2 and beta 3 isoforms by glandula r fibroblasts.