Additionally, in vitro PFOS exposure decreased secretion of TH-1 type cytokines (IL-2 and IFN-γ, specifically) and increased TH-2 type cytokines (IL-4 and IL-10, specifically), indicating a hallmark of atopy disease with polarization towards TH-2 responses, which may contribute to asthma development [88, 89]. This evidence concerns the gene IL4 and asthma.