Collagen biosynthesis in lichen sclerosus et atrophicus studied by biochemical and in situ hybridization techniques

Collagen was studied by biochemical and immunohistochemical techniques and by in situ hybridization in four patients with lichen sclerosus et atrophicus (LSA). The solubility of collagen in acetic acid and pepsin was increased in the lesional skin of the LSA patients when compared with their non-affected skin or samples from control subjects, indicating that a marked proportion of the collagen was newly synthesized. Collagen synthesis was slightly increased in fibroblasts derived from the lesional skin of the LSA patients. In situ hybridization with human sequence-specific cDNAs to type I procollagen demonstrated active fibroblasts in lesional skin of LSA patients, further confirming a high level of collagen synthesis in LSA. Remarkably, active fibroblasts were not associated with inflammatory cell infiltrates noted in LSA skin nor did they express transforming growth factor beta(TGF beta 1). Our results indicate that despite the degeneration of connective tissue, there is an active regeneration process in LSA with significant collagen synthesis.