Objective  To explore the relationship between the abnormal regulation signals of dendritic cells (DCs) and the imbalance of T helper cells during the pathogenesis of Henoch-Schonlein purpura (HSP).   Methods  A total of 58 HSP children

38 boys and 20 girls

at an age of 3 to 16 (mean 7.1) who were admitted in our department from June 2008 to March 2009 were subjected in this study. Another 20 health matched children

12 boys and 8 girls

at an age of 6 to 14 (mean 7.5) served

as control. Their parents all were fully informed the aim and protocol of this study and signed an informed content. This study was approved by the Ethics Committee of our hospital. No hormone or immunosuppressant was used in 4 weeks before blood sampling. Peripheral blood of 5 ml was collected to culture DCs. Immunoglobulin levels were detected by nephelometry assay in children with HSP. Inflammatory cytokines IL-4

INF-γ in blood plasma and IL-12

IL-10 in the supernatants of cultured DCs were detected by ELISA. The count of CD

86

CD

80

CD

83

HLA-DR and CD-209 expressed on DC were detected by cell flow cytometry.   Results  In HSP group

the levels of plasma IgA and IgE were higher than the control group

IL-12 levels in the supernatants of cultured DC and INF-γ levels in the plasma were lower than the control group

and IL10 levels in the supernatants of cultured DCs and IL-4 levels in the plasma were significantly increased than the control group. CD

86

CD

83

and HLA-DR expressed in DCs were significantly higher and CD

80

was significantly lower than the control group (P0.05). CD-209 of 2 groups had no statistical significance (P0.05).   Conclusion  The anomalies of antigen specific signals

costimulatory signals and differentiation or polarization signal of DCs might be involved in Th1/Th2 imbalance and synthesis of abnormal immunoglobulins in pathogenesis HSP.