The apoptosis of blood polymorphonuclear leukocytes in sickle cell disease.

BACKGROUND

The apoptosis of human polymorphonuclear leukocytes (PMNs) in patients with sickle cell disease (SCD) is not well understood. The goal of this study was to examine the apoptosis of PMNs in patients with SCD and in controls.

METHODS

Flow cytometric quantitation of PMN apoptosis was performed in 17 patients during and after sickle cell vasoocclusive crisis and in 17 healthy volunteers. Plasma nitric oxide concentrations were also measured in patients with SCD.

RESULTS

The mean of annexin-V and annexin-V/PI staining (early and late apoptotic cells) increased to a greater degree in patients with SCD than in healthy controls for patients with SCD during and after vasoocclusive crisis. The mean of PI staining showing dead cells was higher only in patients after SCD crisis than in healthy controls. In the SCD groups during and after vasoocclusive crisis, there was no difference between PMN apoptosis levels. Furthermore, plasma nitric oxide concentrations were not correlated with PMN apoptosis.

CONCLUSIONS

There was an evidence that the alteration of blood PMN apoptosis could contribute to the pathogenetic mechanisms of vasoocclusion in patients with SCD. This can be attributed to the effects of numerous inflammatory mediators rather than simply the effects of nitric oxide.