Role of dendritic cells in the pathogenesis of asthma in children / 中华儿科杂志

<p><b>UNLABELLED</b>Dendritic cells (DC) are very potent antigen-presenting cells (APC) with a unique ability to activate naive T cells to induce the differentiation of TH1/TH2. Monocytes can develop into DC in the presence of different cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. DCs are thought to play a key role in the initiation and maintenance of T cell immunity to inhaled antigens. While the density of DC within the bronchial mucosa is increased in asthma, there is little information currently available concerning the effects of DC in asthmatic children.</p><p><b>OBJECTIVE</b>To investigate the role of dendritic cells in the pathogenesis of acute attack of asthma in children.</p><p><b>METHODS</b>Thomas' method was adopted. The adherent precursors of DC were isolated from peripheral blood of asthmatic children in acute attack stage and healthy controls. The adherent cells were induced with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha) to DC in vitro. The expression of the surface molecules CD80, CD86, HLA-DR etc. on the DC was examined by fluorescent activated cell sorter (FACS). And the ability to secret IL-10, IL-12 and their potentials to stimulate the proliferative reaction of DC inductive self T- lymphocyte were observed.</p><p><b>RESULTS</b>The results showed that in asthmatic children's acute attack stage, self T- lymphocyte proliferative reaction induced by DC was remarkably increased compared with normal control subjects (P < 0.01). At the same time, the asthmatic children in acute attack stage had remarkably decreased the ability to secret IL-10 compared with normal control subjects (P < 0.01), while the ability to secret IL-12 remarkably decreased compared with normal control subjects (P < 0.01); meanwhile, the HLA-DR and co-stimulating factor CD86(B(7-2)) expressed by DCs remarkably increased in the asthmatic children in acute attack stage compared with normal control subjects (P < 0.01).</p><p><b>CONCLUSION</b>DC possibly plays a vital role in the immunological mechanism of asthma by means of inducing the differentiation of TH1/TH2, that is DC may be the key factor in initiating the airway allergic reaction and the possible mechanism may involve interleukins (especially IL-10 and IL-12, etc.) secreted by DCs.</p>

Effect of Tpo and/or IL-11 gene modified stromal cells on the expansion of CD34+ CD38- hematopoietic primitive progenitor cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of Tpo and/or IL-11 gene modified stromal cells on the expansion of CD(34)(+) hematopoietic stem/progenitor cells in cord blood.</p><p><b>METHODS</b>Retroviral vectors containing Tpo or IL-11 gene were constructed and used to transfect the stromal cell line HFCL. Tpo and/or IL-11 mRNA was assayed by Northern blot. Non-modified stromal cells were used, CD(34)(+) hematopoietic stem/progenitor cells from cord blood were expanded on gene-modified stromal cells for 7 days. The phenotype of CD(34)(+)CD(38)(-) primitive progenitors was detected by flow cytometry.</p><p><b>RESULTS</b>HFCL expressed Tpo and/or IL-11 mRNA after transfected by the retroviral vectors. The percentages of CD(34)(+)CD(38)(-) primitive progenitors in the cultures of Tpo, IL-11 and Tpo + IL-11 modified HFCL were (1.8 +/- 0.24)%, (1.62 +/- 0.23)%, and (2.45 +/- 0.28)%, respectively, which were higher than that in the control [(0.8 +/- 0.23)%].</p><p><b>CONCLUSION</b>The stromal cells modified by Tpo and/or IL-11 gene were able to enhance ex vivo expansion of CD(34)(+) and CD(34)(+)CD(38)(-) hematopoietic stem/progenitor cells from cord blood.</p>