In vitro effect of iron overload on bone marrow cell function by inducing the reactive oxygen species / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the in vitro effect of iron overload on the generation of reactive oxygen species (ROS) and of bone marrow (BM) cell function.</p><p><b>METHODS</b>BM mononuclear cells (BMMNCs) were cultured with ferric citrate (FAC) at different concentrations and for different time to create iron overload and confirmed by the detection of cellular labile iron pool (LIP). The changes of ROS, apoptosis, hematopoietic colony formation (CFU-E, BFU-E, CFU-GM and CFU-mix) and the percentage of the CD34 + cells percentage were analyzed. The differences of these index were tested after the iron overload treated with deferasirox (DFO) or antioxidants (N-acetyl-L-cysteine, NAC).</p><p><b>RESULTS</b>1) When BMMNCs were cultured with FAC, the LIP was found to increase in a time and concentration dependent manner. The intracellular LIP reached maximum at 400 micromol/L of FAC for 24 hours. 2) The ROS of total cells, leukocytes and erythrocytes increased to 1.77, 1.75 and 2.12 fold respectively compared with that of normal control when cells were cultured at 400 micromol/L of FAC for 24 hours . DFO and NAC could reduce the ROS efficiently (P<0.05). 3) The apoptotic rates of the FAC treated cells [(24.80 +/- 2.99)%] increased significantly compared with that of normal control [(8.90 +/- 0.96)%]. The capacity of hematopoietic colony formation in FAC treated cells decreased markedly compared with that of normal control (P<0.05). The percentage of CD34+ cells of FAC treated cells [(0.39 +/- 0.07)%] also decreased significantly compared with that of normal control [(0.91 +/- 0.12)%]. And these changes could be recovered by addition of NAC or DFO.</p><p><b>CONCLUSION</b>Iron overload can affect the hematopoiesis by inducing the generation of ROS and this damage could be corrected by removing the excess iron and ROS of the BM cells. These findings might improve the treatment of dyshematopoiesis in patients with iron overload.</p>

Effects of interleukin 21 on anti-leukemia activity of cytotoxic T lymphocytes induced by dendritic cells / 中国实验血液学杂志

This study was aimed to explore the effects of interleukin 21 (IL-21) on the anti-leukemia activity of cytotoxic T lymphocytes (CTL) induced by dendritic cells (DCs) in vitro. The peripheral mononuclear cells from leukemia patients in complete remission were cultured with the specific cytokines to induce the production of DCs. The DCs loaded with RNA from autologous leukemic cells as antigen, and co-cultured with autologous T lymphocytes to get leukemia specific CTL. The cytotoxic activity of CTL against autologous leukemic cells was measured by LDH release method. The concentration of IFN-gamma and TNF-alpha in the culture supernatant was measured by enzyme immunoassay. The effects of IL-21 on the mature DCs were also studied by the measurement of the phenotype of DC and the allogenic mixed lymphocytic reactions induced by DCs. Experiments were divided into 2 groups: test group in which IL-21 (200 ng/ml) was added in coculture of DC/CTL and control group in which no IL-21 (200 ng/ml) was added. The results showed that when cultured with IL-21, the quantity of CTL increased from (56.73 +/- 10.21)% (control group) to (73.43 +/- 18.01)% (p < 0.01); The concentration of IFN-gamma and TNF-alpha in the culture supernatant increased from (154.91 +/- 67.20) ng/L (control group) to (310.62 +/- 141.15) ng/L (p < 0.01) and from (8.77 +/- 5.09) microg/L (control group) to (15.25 +/- 6.56) microg/L (p < 0.01) respectively. At the effector: target ratio of 20:1, the cytotoxic activity against autologous leukemic cells by CTL increased from (50.22 +/- 5.07)% (control group) to (75.38 +/- 9.47)% (p < 0.01). IL-21 had neither effect on the phenotype (CD1a, CD83, CD86, CD80 and HLA-DR) of mature DCs nor the allogeneic mixed lymphocytic reactions induced by DCs. It is concluded that IL-21 can strengthen the proliferation of CTL, and improve the production of IFN-gamma and TNF-alpha, thus enhance the anti-leukemia activity of CTL. Nevertheless, there is no effect of IL-21 on the function of mature DCs. These data indicate that IL-21 has a potential clinical value in the enhancement of anti-leukemia immunotherapy.