Sj-Cys, a cysteine protease inhibitor secreted by S. japonicum, is a strong immunomodulator that alleviates excessive inflammation caused by bacteremia through stimulating IL-10 and TGF-β1 cytokines and reducing pro-inflammatory cytokines TNF-α, IL-6, IL-1β, possibly acts on macrophages or other effective immune cells via downregulation of the TLR adaptor-transducer MyD88. This evidence concerns the gene MYD88 and bacterial infectious disease with sepsis.