In severe sickle cell anaemia the level of haemoglobin F which improves the outcome of the disease is low.19 Low haemoglobin F leads to increased sickling and expression of adhesive molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-4 (ICAM-4), and basal cell adhesion molecule (BCAM).16 These molecules cause the erythrocytes to stick to themselves and the endothelium of the blood vessels.16 They could also cause adherence to the macrophages, with subsequent erythrophagocytosis and haemolysis. Here, ICAM4 is linked to sickle cell disease.