Although PPAR-γ activation has been implicated as an important contributor to the pathogenesis of the toluene diisocyanate–induced asthma phenotype in a female BALB/c mice model (Lee et al. 2006), PFOS and PFOA have been shown to significantly increase activation of mouse or human PPAR-α and PPAR-β, but not of PPAR-γ, in vitro (Takacs and Abbott 2007). This evidence concerns the gene PPARD and asthma.