Cytokine mRNA expression in pleural exudate cells from guinea pigs with tuberculous pleurisy. Expression of TGF-β1 mRNA (A), expression of TNF-α mRNA (B), expression of IFN-γ mRNA (C), and expression of IL-8 mRNA (D) were measured in pleural fluid cells obtained from control and anti-TGF-β1-treated guinea pigs with experimental tuberculous pleurisy. The level of induction was determined from the threshold cycle values normalized for 18S expression and then normalized to the values derived from resident pleural cells of healthy, pleuritis-free animals. The bars indicate the means for three or four animals, and the error bars indicate the standard errors of the means. An asterisk indicates that there is a significant difference between mRNA expression in cells from treated animals and mRNA expression in cells from control animals.