[Role of dendritic cells in the pathogenesis of asthma in children].

UNLABELLED: 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. OBJECTIVE: To investigate the role of dendritic cells in the pathogenesis of acute attack of asthma in children. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

[Activation of nuclear factor kappa B in newborn rats sepsis].

OBJECTIVE: The aim of the study is to explore the effect of NF-kappa B signal pathway in neonatal sepsis so as to provide the experimental base for corresponding clinical treatment of the sepsis, in which NF-kappa B is taken as the target. METHODS: The sepsis model was established in newborn rats by giving Staphylococcus aureus subcutaneously: (1) The electrophoretic mobility shift assay (EMSA) was used to observe the activity of NF-kappa B in the lungs and the livers in newborn rats with Staphylococcus aureus sepsis. (2) Immunohistochemical method was used to observe the activity of NF-kappa B P56 in newborn rats with Staphylococcus aureus sepsis. (3) The anti-oxidant pyrrolidine dithiocarbamate (PDTC) was used to observe its effect on NF-kappa B activities of liver and lungs and on the activity of splenic NF-kappa B P56 in newborn rats with Staphylococcus aureus sepsis. RESULTS: In newborn rats with Staphylococcus aureus sepsis, the NF-kappa B activity in lungs was enhanced at the 1st hour and reached to the peak level at the 3rd hour; then, it was weakened gradually and at the 24th hour faded away. The activity of the liver NF-kappa B was also activated and peaked at the 4th hour; then, it was gradually weakened and at the 24th hour faded away. The positive expression of splenic NF-kappa B P56 began to be intensified at the 1st hour (12.0 +/- 3.7), peaked at the 3rd hour (51.4 +/- 5.9) and showed insignificant differences at the 24th hour (3.4 +/- 1.4) as compared with the sepsis group. PDTC had an inhibitive effect on the activities of liver NF-kappa B and lung NF-kappa B and on the positive expression of splenic NF-kappa B P56 used in the dosage of 50-200 mg/kg. The larger the dosage was used, the more intensified inhibitive effect could be obtained. In the dosage of 200 mg/kg, the inhibitive effect was the most intensified. CONCLUSIONS: (1) In newborn rats with Staphylococcus aureus sepsis, the NF-kappa B of lungs, liver and spleen were activated, and all indicate a peak. (2) The anti-oxidant PDTC can inhibit NF-kappa B activity in a dose-effect fashion in newborn rats with Staphylococcus aureus sepsis.