MBTPS1 and idiopathic pulmonary fibrosis: Given the direct association between plasma S1P levels and IPF mortality and animal models of lungs [3,4,15,20] and that SPHK1 inhibition mitigates bleomycin-induced increases in plasma SIP levels [15], we assessed whether PF543 ameliorates plasma S1P levels when administered every other day at 1mg/kg [35,36].