To study whether the effects of SF on α-sma expression could be induced by TGF-β in the SF, healthy FLSs were stimulated with 1 ng/ml TGF-β (the level of total TGF-β normally found in RA SF [28]) and expression of collagen I, α-sma and TLH was measured. The gene discussed is ACTA1; the disease is rheumatoid arthritis.