Filtration of sickle cells is sensitive to factors that enhance polymerization of haemoglobin S

Rheological methods have considerable potential for the study of sickle cell disease. We have developed a 5 µm pore filtration technique to detect the loss of deformability of sickle cells that occurs secondary to polymerization of haemoglobin S. Loss of filterability was shown to be sensitive to enhancement of polymerization caused by rise in temperature, fall in pH, increase in haemoglobin concentration secondary to cell dehydration, and decrease in oxygen tension. Initial-flow-rate filtration of sickle cells through pores of 5 µm diameter can therefore be used to study the pathogenesis of vaso-occlusive events in sickle-cell patients, to screen potential anti-sickling drugs in vitro, and to monitor the efficacy of such drugs in clinical trials.