A study of 309 patients by Ryu et al found that IL-5, CCL-11, CCL-24, IFN-γ, and periostin increased with ageing in CRS phenotypes when compared with controls, while IL-17A, CXCL-8, and IL-6 decreased with ageing.55 Study quality was strengthened by a large sample size and adjustment of outcomes for confounding factors such as atopy status, smoking history, and disease duration. This evidence concerns the gene CXCL8 and congenital rubella syndrome.