Also, the role of MIF in human disease has been recently emphasized since it has been suggested that polymorphisms modifying MIF expression could be associated with severe rheumatoid arthritis, fibrosis and asthma (Baugh et al., 2002; Donn et al., 2002; Mizue et al., 2005; Plant et al., 2005; Renner et al., 2005). Here, MIF is linked to asthma.