Background: IL-1 Rationale for blocking IL-1 in Systemic Sclerosis: The inflammasome and fibrosis Several observations have implicated IL-1 in fibrotic diseases and SSc. Environmental or occupational exposure to silica dust leads to fibrosis (Cohen et al., 2008) and has been associated with SSc (Rustin et al., 1990). Recently, several groups have shown in murine models that silica dust activates inflammation and fibrosis through the inflammasome (Cassel et al., 2008; Hornung et al., 2008) . Activation of the inflammasome also contributes to bleomycin-induced lung injury (Gasse et al., 2007).