Figure 2.

Correlation between theophylline actions on HDAC activity and clinical parameters. (a and b) Correlation between changes in HDAC activity induced by theophylline and theophylline-induced changes in PC₂₀ (concentration that provokes a 20% change in FEV) for methacholine (a) and inhibition of sputum eosinophils (b). (c) Correlation between HDAC activity and sputum eosinophils in normal and asthmatic subjects. (d) No correlation between FEV₁ (forced expiratory volume in 1 s) and theophylline-induced HDAC activity. Dotted lines represent 95% confidence limits.