The study will be conducted at 15-20 US centers in a randomized, placebo-controlled, double-blind fashion. Enrollees will be hospitalized sickle cell disease (SCD) patients at-risk for acute chest syndrome (ACS) based on the presence of vaso-occlusive crisis (VOC), fever (T ≥38.0°C) and serum sPLA2 concentration ≥50 ng/mL.