graduate student Department of Hematology ,The Second Affiliated Hospital of Kunming Medical University Kunming, Yunnan, China (People's Republic)
Background: Dendritic cells(DCs) are closely related to the pathogenesis of immune thrombocytopenia（ITP）, but the details are not unclear.We for the first time investigated the biological characteristics and functions of CD83 in DCs .
Aims: To explore the relationship between CD83 and CD4+T cell subsets and clarify the role of CD83 in ITP autoimmunity regulation.
Methods: The expression of CD4+、CD25+、FoxP3 and CD83+ on CD4+T cells was detected by flow cytometry. CD83, GATA-3, TGF-β, IL-10, FoxP3, TLR4, T-bet were detected by QPCR. The concentration of sCD83 was determined by ELISA. DCs were transfected with siRNA-CD83, NC(negative control);and plasmid overexpressed DC-CD83(pcDNA) ,pEX-1 (negative control) ; Blank control. The DCs was co-cultured with CD4+T cells 1:5 and 1:10 for 72 hours. The concentrations of IFN-γ, IL-17, TGF-β and IL-10 were detected by ELISA.The DCs was co-cultured with CD4+T cells 1:10 to detect Tregs.
Results: The expression levels of CD4+CD25+FoxP3 and CD83+CD4+CD25+FoxP3 were higher in the control group (p>0.05）. The expression of CD4+CD83+ was higher in ITP group（p>0.05）. CD83 and TLR4 in ITP group were higher than those in control group, while GATA-3, IL-10 and FoxP3 were lower than those in control group, with statistical significance. TGF-β and T- bet had no significant difference between the two groups. sCD83 was higher in ITP group (p=0.001). siRNA inhibited the proliferation of CD4+T cells, while pcDNA promoted the proliferation of CD4+T cells（Figure 1）. The IFN-γ and IL-17 levels in pcDNA group were higher than those in siRNA group. Both IL-10 and TGF-β were lower than those in siRNA group（Figure 2）. Overexpression of CD83 promoted the up-regulation of Tregs, pcDNA vs siRNA in ITP group (p < 0.0001). Control group pcDNA vs siRNA (p < 0.0001).
Conclusion(s): siRNA-CD83 inhibits CD4+T cell proliferation by interfering with dendritic cells, reverse the imbalance of Th1/Th2 and Th17/Treg in ITP patients .
.jpg "Xiuli Wang, MA photo")