CTSS and systemic lupus erythematosus: Furthermore, CTSS-overexpressing mice showed a marked increase in the production of IL-17, TNF-α, IFN-α and IFN-γ, which are known to be associated with lupus development, and the chemoattractants CCL2, CCL7 and CCLl12, which are activated by IFN-α to attract monocytes to inflammatory sites.