To determine whether the propensity to develop a lung disease phenotype was evident early on in a more clinically accessible tissue, serum cytokine levels were measured and are shown in Figure 4A. Serum cytokine levels of IL6, Il10 and Il13 were found to depend on strain at all assay times while a significant strain effect in Il1β, Ifnγ and Tnfα was observed for all time points with the exception of control. Here, IL13 is linked to lung disorder.