IL13 and keratoconus: While no significant change was found in KC/GRO and IL-4 levels subsequent to carrageenan injection (Figure 3E, F), an increase in TNF, IL-1β, IL-13, and IFN-γ concentrations were detected in CSF 2 hours after injection of carrageenan to the hind paw as compared to the vehicle (PBS) injected control group (Figure 3A-D).