THE METABOLITES OF NITRIC-OXIDE IN SICKLE-CELL DISEASE

Plasma NOx concentrations were raised in 22 acute painful crises in SCD. We have measured blood concentrations of nitric oxide metabolites (NOx) in sickle-cell disease (SCD), and shown that they are increased compared with healthy controls (P=0.002), and haemoglobin E/beta-thalassaemic controls (P=0.05), Concentrations in steady-state: SCD were also higher than in healthy controls (P=0.04) but not significantly different from the concentrations at the beginning of painful crises (P=0.34). Importantly. in 12 regularly exchanged sicklers, the mean pre-transfusion NOx concentration did not differ significantly from the control population (P=0.52), suggesting that the changes in NO metabolism can be reversed, It is unlikely that the increased concentrations of NOx in SCD result from anaemia or haemolysis as the untransfused haemoglobin E/beta-thalassaemics did not show increased levels.