GSTM1 and non-autoimmune hemolytic anemia: It is well known that haemoglobin (Hb) in circulating red blood cells (RBCs) acts as a high‐affinity depot or storage pool for nitric oxide (NO)1 and that, cell‐free Hb, an even more avid scavenger of NO, contributes to the pathology of haemolytic anaemias like sickle cell disease, malaria and transfusion of older stored blood.2 Less well known is that nitrite enzymatically reacts with deoxyhaemoglobin to generate nitric oxide in the RBC, which serves as an “erythrocrine,” that is endocrine carrier and exporter of NO.