[A study of phenotype and function of dendritic cells and secretory cytokine in allergic asthmatic patients].

ABSTRACT

OBJECTIVE: To investigate the deficiency of the expression of the phenotypes (CD(1a), CD(83), CD(40), CD(86)) and cytokines (IL-12 and IL-10) by human peripheral blood monocyte (PBMC)-derived dendritic cell (DCs) from asthmatic subjects, and their influence on naive T cell polarization. METHODS: Adherent cells were isolated from peripheral blood samples in asthmatic patients and in healthy volunteers, and were cultured with granulocyte-macrophage colony-stimulating factor and IL-4 as immature DC (iDC). iDCs were stimulated with lipopolysaccharide as mature DC (mDCs). Nonadherent cells were obtained from umbilical cord blood by idem methods, and naïve T cells were sorted by adding anti-CD(4) and anti-CD(45RA) in nonadherent cells respectively and magnetic microbeads. Naïve T cells and mDCs from two groups were co-cultured in complete RPMI1640 media respectively, and naive T cells polarized as T helper cells 1 (Th1) and Th2. The expression of the CD(1a), CD(83), CD(40) and CD(86) on mature DCs were examined by fluorescent activated cell sorter. IL-12 and IL-10 released by mDCs and IL-4 and IFNgamma produced by Th cells were measured by ELISA. RESULTS: (1) The expression of CD(86) on dendritic cells from atopic asthmatics was higher than that from healthy control subjects (40.75 +/- 3.99 vs 29.88 +/- 1.25, P < 0.01). (2) The levels of IL-12, IL-12p40 and IL-10 produced by DCs from asthmatic subjects were all significantly lower than those from healthy control group (217.79 +/- 118.65 vs 905.66 +/- 495.32, P < 0.01; 2072.22 +/- 1496.37 vs 5569.43 +/- 2922.75, P < 0.01; 336.89 +/- 261.52 vs 1425.00 +/- 1148.87, P < 0.05, respectively). (3) IL-4 production by Th2 cells which were primed by DCs from asthmatics was significantly increased as compared to that from control group (368.56 +/- 190.72 vs 584.91 +/- 290.13, P < 0.01); On the contrary, IFNgamma in the patient group was reduced as compared to that in the control group (425.33 +/- 164.94 vs 49.86 +/- 18.14, P < 0.05). (4) In the patient group, the level of IL-12 was positively correlated to that of IFNgamma (P < 0.05), negatively correlated to that of IL-4 (P < 0.05); IL-10 was negatively correlated to IL-4 (P < 0.05). (5) There was a positive correlation between IL-12 and IL-10 in the two groups (P < 0.01). CONCLUSION: Because of DC deficiency, naïve T cells preferentially polarize to Th2 which synthesize more Th2-type cytokine (i.e. IL-4) and T cell tolerance cannot be induced, which may be one of the important pathogenic mechanisms for allergic asthma.