Cytolytic cytokine formed in the cytolytic granules of activated cytotoxic T cells (CD8) and NK cells. It is active together with the cytokine perforin. Perforin is integrated into the cell membrane of the target cell where it forms a pore-like structure. Certain serine proteases (granzymes) penetrate through this pore into the target cell and induce apoptosis. Granulysin has a broad antimicrobial effect. It leads to the destruction of keratinocytes in certain inflammatory processes of the skin, e.g. in Stevens-Johnson syndrome or TEN. The concentration of granulysin in the bladder contents is directly correlated to the severity of the disease.