1. The formation of polymerized haemoglobin S in sickle cells is critically dependent on the concentration of deoxygenated haemoglobin so that compounds which increase the oxygen affinity of haemoglobin S are potential anti-sickling agents.
2. BW12C [5-(2-formyl-3-hydroxyphenoxy)pentanoic acid] and BWA589C [4-(2-formyl-3-hydroxyphenoxymethyl)benzoic acid] are aromatic benzaldehydes that cause a dose-dependent left-shift of the oxygen saturation curve of haemoglobin S by stabilization of its oxy-(R)-conformation.
3. A 5 μm pore filtration method, which is highly sensitive to polymerization of haemoglobin S, was used to demonstrate a significant improvement in the deformability of deoxygenated sickle erythrocytes at concentrations (0.75–1.5 mmol/l) of BW12C and BWA589C that are achievable in vivo. Both compounds may therefore be of value for the treatment of sickle cell disease.
4. Filtration of sickle cells through pores of 5μm diameter is a sensitive technique for evaluating the rheological effects of potential anti-sickling compounds.