Immunofluorescence analysis of collagen, fibronectin, and basement membrane protein in scleroderma skin.

Scleroderma skin and the subcutaneous tissue was studied by indirect immunofluorescence with specific antibodies against interstitial collagens and procollagens, against fibronectin and against the basement membrane proteins Type IV collagen and laminin. Staining for Type I procollagen and fibronectin was distinctly increased in the lower dermis and subcutaneous tissue. When compared with normal skin the data suggests that fibrosis may start around capillaries and in close proximity to adipose cells. Additional changes in the distribution to Type IV collagen and laminin were found in some patients and probably reflect the alterations in small blood vessels.