Immunohistochemical demonstration of proteoglycans in the skin of patients with systemic sclerosis.

Skin proteoglycan was demonstrated by an immunofluorescent technique using an antibody against bovine cartilage proteoglycan, after the cross-reactivity of human proteoglycan with the antiserum had been confirmed. Normal skin exhibited specific fluorescence mainly in the blood vessels as well as in the subepidermal area. The clinically uninvolved skin of systemic sclerosis (SS) revealed no features different from those of normal skin. However, the vascular proteoglycan deposition of early systemic sclerosis was later replaced by deposition between the collagen fibres, which appeared to progress centrifugally in parallel to the increase in the skin sclerosis, suggesting a vascular initiation of the skin lesion. Sclerotic skin was characterized by random deposition between the collagen fibres. Immunoelectron microscopic studies suggested that the random proteoglycan deposition reflected uncontrolled local accumulation of proteoglycan in the interfibrillar matrix around irregularly arranged collagen fibrils.