Abstract
Background Dendritic cells (DC) are critical effectors of innate and adaptive immunity, acting both as sentinels that detect the presence of pathogens and as key antigen-presenting cells that regulate the adaptive immune response. Therefore, DC play a crucial role in the control of autoimmune responses. We previously showed that blood DC numbers were strongly reduced in ANCA-associated vasculitis (AAV) likely due to their recruitment in tissues. Here, we assessed the ex vivo responsiveness of blood DC from AAV-patients to Toll-like receptors (TLRs) stimulation. Materials and methods Blood samples from 10 untreated patients with AAV during flares and before any immunosuppressive treatment (AP) were analyzed, along with 9 AAV patients in remission (RP) and 11 age-matched healthy controls (HC). Intracellular cytokine (IL-12, TNF-a ,I FN-a) production by blood DC was assessed by 8-colors flow cytometry after stimulation by Toll-like receptors of whole blood samples. Results We found that myeloid DC (mDC) from patients in acute phase exhibited a decreased IL-12 production after TLR3, 4 and 7/8 stimulation compared to patients in remission and healthy controls. These mDC also produced less TNF-a after TLR3 stimulation. Moreover, we observed a reduction in the frequency TNFa-producing plasmacytoid DC (pDC) upon TLR7/8 triggering in AP patients compared to RP patients and HC. Conclusion
Highlights
Dendritic cells (DC) are critical effectors of innate and adaptive immunity, acting both as sentinels that detect the presence of pathogens and as key antigen-presenting cells that regulate the adaptive immune response
We previously showed that blood DC numbers were strongly reduced in ANCA-associated vasculitis (AAV) likely due to their recruitment in tissues
We found that myeloid DC from patients in acute phase exhibited a decreased IL-12 production after TLR3, 4 and 7/8 stimulation compared to patients in remission and healthy controls
Summary
Altered innate functions of myeloid dendritic cells in ANCA-associated vasculitis. From 7th European Workshop on Immune-Mediated Inflammatory Diseases Noordwijk aan Zee, the Netherlands. From 7th European Workshop on Immune-Mediated Inflammatory Diseases Noordwijk aan Zee, the Netherlands. 28-30 November 2012
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