Baruch and colleagues [37] found that the decline in the IL-4: IFN-γ ratio with increased levels of IL-4 in the choroid plexus, affected function, morphology, and expression of junctional proteins at the BCSFB, suggesting that a predominance of Th2 cytokines alter epithelial-T lymphocyte crosstalk, which is detrimental to the choroidal epithelium, and that this could be another example of epithelial pathologies mediated by a Th2 inflammation, such as the lung epithelium in asthma. Here, IL4 is linked to asthma.