PT - JOURNAL ARTICLE AU - M. Martinez-Losa AU - J. Cortijo AU - G. Juan AU - M. Ramón AU - M. J. Sanz AU - E. J. Morcillo TI - Modulatory effects of <em>N-</em>acetyl-<span class="sc">l</span>-cysteine on human eosinophil apoptosis AID - 10.1183/09031936.00073706 DP - 2007 Sep 01 TA - European Respiratory Journal PG - 436--442 VI - 30 IP - 3 4099 - http://erj.ersjournals.com/content/30/3/436.short 4100 - http://erj.ersjournals.com/content/30/3/436.full SO - Eur Respir J2007 Sep 01; 30 AB - Eosinophils are oxidant-sensitive cells considered relevant in allergic inflammation. The present study aimed to examine the effects of the antioxidant N-acetyl-l-cysteine (NAC) on constitutive and cytokine-delayed apoptosis in human isolated eosinophils. Human eosinophils were purified from the blood of healthy donors by a magnetic separation system. Apoptosis and cellular glutathione were assessed by cytofluorometric analysis and nuclear factor (NF)-κB binding activity assessed by electrophoresis mobility shift assay. The rate of spontaneous apoptosis of human eosinophils after 24 h culture, as assessed by annexin-V-positive staining, was mean±sem 48.2±1.4%, n = 5. Granulocyte-macrophage colony-stimulating factor (GM-CSF; 10 ng·mL−1) decreased apoptosis to 19.4±1.8%, n = 5. NAC (5 mM) inhibited spontaneous apoptosis (33.6±2.7%, n = 5) but augmented apoptosis in the presence of GM-CSF (30.9±1.5%, n = 5). NAC (5 mM) also increased the rate of apoptosis in the presence of tumour necrosis factor (TNF)-α (10 ng·mL−1) and interleukin-5 (5 ng·mL−1). NAC (5 mM) increased eosinophil glutathione content. The increase in eosinophil NF-κB binding activity induced by GM-CSF and TNF-α was suppressed by NAC. In conclusion, N-acetylcysteine modulates eosinophil apoptosis by inhibiting constitutive apoptosis but reversing the survival effect produced by inflammatory cytokines in human eosinophils.