Regarding the antivirulence activity of AZM in humans, a retrospective study observed a correlation between the inhibitory effect of AZM on PLC production by P. aeruginosa strains isolated from CF patients and the observed FEV1 improvement after AZM therapy (Nguyen et al., 2007), suggesting that in vivo PLC production is a main target of AZM. The gene discussed is HSPG2; the disease is cystic fibrosis.