DEMONSTRATION OF INCREASED LEVELS OF TYPE-I COLLAGEN MESSENGER-RNA USING QUANTITATIVE POLYMERASE-CHAIN-REACTION IN FIBROTIC AND GRANULOMATOUS SKIN DISEASES

Collagen changes occur in localized scleroderma, scleredema and sarcoi dosis. Previous biochemical, immunohistochemical and in situ hybridiza tion studies have revealed increased collagen synthesis in these disea ses, In the present study, we measured the pro alpha 1(I) collagen and beta-actin mRNA levels in skin punch biopsy specimens from lesional a nd healthy skin using a quantitative polymerase chain reaction (PCR). In this method, the targeted mRNA and a synthetic RNA as a internal st andard are co-amplified together with the same primers. The amount of pro alpha 1(I) collagen mRNA in cutaneous sarcoidosis lesions was foun d to be increased about two- to threefold compared with the values obt ained for the healthy skin of the same two patients. In lesional skin of three patients with localized scleroderma the number of pro alpha 1 (I) collagen molecules was increased about two-fold. The beta-actin mR NA values were at the same level in the affected and unaffected skin o f all the patients studied. In conclusion a marked increase in type I collagen gene expression was seen in localized scleroderma and sclered ema, leading to fibrosis of the skin, and in a granulomatous skin dise ase, cutaneous sarcoidosis.