We have demonstrated an immune deviation towards Th1 cytokine bias in a proportion of women with PTD [79]; PBMC from women with normal pregnancy produce higher levels of the Th2 cytokines IL-4, IL-5 and IL-10, while the Th1 cytokines IL-2 and IFN-γ are produced at greater concentrations by women with PTD. Here, IL4 is linked to Bjornstad syndrome.