GSTM1 and acute chest syndrome: The main recommendations for RBC transfusion for patients with SCA are as follows: a decrease in Hb ≥2 g/dL compared to baseline values and/or the presence of an acute complication such as a vaso-occlusive refractory crisis to conventional treatment, acute chest syndrome, splenic or hepatic sequestration, transitory aplastic crisis, or hemodynamic decompensation10,.12