Interleukin-4(IL-4) is a 20 kDa glycoprotein and is now known to possess fibrogenic activities.

The purpose of this study is to evaluate the effect of IL4 on the extracellular matrix gene expression.

Quantitation of collagenous protein synthesis, Northern and dot-blot hybridization, transfection experiments and CAT assay in normal human skin fibroblasts were done.

Maximal elevation of collagen synthesis was presented at the concentration of IL-4 being S.Ong/ml. In Northern and dot-blot analysis, each level of type I collagens and fibronectin mRNA increased 3.0, and 2.8-fold, respectively in IL4 treated fibroblasts. In CAT to c assay, the percentage of acetylation was 8.3% in the untreated control group and 23.1% in 5.Ong/ml of the IL-4 treated group in normal fibroblasts. The promoter activity was in creased 2.8-fold in II.4(5.Ong/ml) treated fibroblasts compared to the control groups.

IL4 might be a fibrogenic cytokine that could be important in promoting the biogenesis of collagen proteins. This could be due to increased transcription.