Impaired Blood Dendritic Cell Numbers and Functions after Aneurysmal Subarachnoid Hemorrhage

Antoine Roquilly (1, 2) , Cécile Braudeau (3, 4, 5) , Raphael Cinotti (1) , Erwan Dumonte (5) , Rémi Motreul (6) , Régis Josien (3, 4, 5) , Karim Asehnoune (1, 2)

1 EA 3826 - Thérapeutiques cliniques et expérimentales des infections (EA 3826)
2 Service d'anesthésie et réanimation chirurgicale [Nantes]
3 U1064 Inserm - CRTI - Centre de Recherche en Transplantation et Immunologie
4 ITUN - Institut de transplantation urologie-néphrologie
5 Centre d’Immunomonitorage Nantes Atlantique - CIMNA - Laboratoire d’Immunologie [CHU Nantes]
6 Anesthésie Réanimation chirurgicale [CHU Nantes]

PREVIOUS PRESENTATION: Portions of this study were presented at the Annual Congress of Société Française d'Anesthésie et de Réanimation in Paris, September 2012. BACKGROUND: Toll-like receptor (TLR) agonists are promising therapy for the prevention of nosocomial infections in critical ill patients. We aimed to analyze the TLR-reactivity of circulating dendritic cells (DC) as assessed by cytokine production after an ex vivo challenge with TLR agonists in aneurysmal subarachnoid hemorrhage (SAH) patients. METHODS AND FINDINGS: A single-center prospective observational study took place in one intensive care unit of a teaching hospital. Blood samples were harvested on days 2, 5 and 10 in 21 severe SAH patients requiring mechanical ventilation and 17 healthy controls. DC production of cytokines (Tumour Necrosis Factor, TNF-α; Interleukin, IL-12; and Interferon, IFN-α) was assessed by intracellular immunostaining on TLR-3, 4, 7/8 and 9 stimulations. SAH patients had decreased numbers of blood myeloid (mDCs) and plasmacytoid DCs (pDCs) on days 2, 5 and 10. Compared with the healthy controls, the frequency of mDCs producing TNF-α after TLR-3 stimulation was decreased in the SAH patients. The frequency of myeloid DCs producing IL-12 after TLR-3 and 4 stimulations was also decreased in the SAH patients. In contrast, the mDCs response to TLR-7/8 was not impaired in the SAH patients. The frequency of pDCs producing TNF-α(+) and IFN-α(+) on TLR-7/8 stimulation were reduced at all of the tested times in the SAH patients, whereas reactivity to TLR-9 was preserved. On day 2, the pDCs from non-survivor patients (n=8) had a decreased ability to produce IFN-α on TLR-9 stimulation compared with the survivors. CONCLUSIONS: These data suggest functional abnormalities of circulating pDCs and mDCs that could be important for immunomodulation after SAH.

Domaines: Médecine humaine et pathologie

Antoine Roquilly, Cécile Braudeau, Raphael Cinotti, Erwan Dumonte, Rémi Motreul, et al.. Impaired Blood Dendritic Cell Numbers and Functions after Aneurysmal Subarachnoid Hemorrhage. PLoS ONE, 2013, 8 (8), pp.e71639. ⟨10.1371/journal.pone.0071639⟩. ⟨inserm-02164641⟩