Ildefonso Sánchez Cerrillo1, Marta Calvet Mirabent1, Ana Triguero2, Diego Calzada Fraile3, Mariel Valdivia1, Marta Ramírez3, Enrique Vázquez de Luis3, Alberto Benguría Filippini3, Roberto Moreno3, María Magdalena Adrados de llano1, Hortensia de la Fuente1, Ilya Tsukalov4, Emilia Roy Vallejo5, Almudena Ramiro3, Salvador Iborra6, Francisco Sánchez Madrid1, Ana Dopazo3, Isidoro Gonzalez7, Santos Castañeda8 and Enrique Martín Gayo4, 1Hospital La Princesa, Madrid, Spain, 2Hospital Universitario La Princesa, Madrid, Spain, 3Centro de Investigaciones Cardiovasculares, Madrid, Spain, 4Universidad Autónoma de Madrid, Madrid, Spain, 5Internal Medicine Department, Hospital Universitario La Princesa, Instituto de Investigación Sanitaria La Princesa (IIS-IP), Madrid, Spain, 6Universidad Complutense de Madrid, Madrid, Spain, 7Hospital Universitario de La Princesa, Madrid, Spain, 8Division of Rheumatology, Hospital Universitario de La Princesa, IIS-Princesa, Madrid, Spain
Background/Purpose: Altered Th17, CD8+ T cell and B cell adaptative immune responses in patients with primary Sjögren syndrome (pSS) have been characterized in salivary glands (SG). However, although innate cells such as natural killer (NK) and dendritic cells (DC) have been observed in the SG. However, their potential cellular and molecular mechanism involved in activation of NK cells in pSS have been less investigates. We identify a dendritic cell subset with phenotypic and functional characteristics capable to boost NK cells and defined pathogenic crosstalk between NK cells and adaptative Th17 CD4+ T cells.
Methods: PBMCs from 40 pSS patients and 42 healthy donors (HD) were used for phenotypical analysis of myeloid and NK cell subsets by flow cytometry. Sorted Mo, CD1c+ and CD141+ cDC from each cohort were used to RNA-seq analysis and co-culture with sorted NK cells for test functional interactions. Regulation of ligands for NK cell receptors on cDC was analyzed after stimulation with poly I:C using specific siRNAs. Finally, DC and NK cell phenotypes and interactions with adaptative immune cells were analyzed using an experimental SS model induced by injections of poly I:C in combination with an NK cell-depleting antibody.
Results: We identified enriched proportions of transitional CD16+ CD56hi NK cells in pSS patients characterized by increased levels of NKG2D (p< 0,0001), IFNg and TNFa (p=0.01) and increased cytotoxic activity in pSS individuals compared to HD. In addition, we detected significantly basal higher expression (p=0.001) of Slamf7 and MICab (p< 0.0001) on circulating CD1c+ cDC exhibiting transcriptional signatures involving the RIG-I/DDX60 RNA sensors and their target genes. This phenotype was associated with higher functional ability of CD1c+ cDC to activate cytotoxic NK cells ex vivo compared to other myeloid subsets. Importantly, expression of MICab was more efficiently induced on cDCs from pSS than cDCs from HD after stimulation with poly I:C and was dependent on expression of RIG-I, DDX60 intracellular RNA sensors. Importantly, more mature cytotoxic NK cells exhibiting upregulated NKG2D and CD64hi CD1c+ cDC expressing higher levels of RAE-I were detected specifically in the SG in a murine SS model. Finally, NK cell depletion was associated with reduced levels of IL-17 in CD4+ T cells, IFNg+ CD107a+ CD8+ T cells and proportions of B220+ B cells in the SG from this murine SS model.
Conclusion: Thus, our study provides new evidence supporting a role of NK cells during pSS pathology and adds novel mechanisms in the crosstalk between innate and adaptative immune system that could contribute to pSS pathology and be used as target for future therapies.
Disclosures: I. Sánchez Cerrillo, None; M. Calvet Mirabent, None; A. Triguero, None; D. Calzada Fraile, None; M. Valdivia, None; M. Ramírez, None; E. Vázquez de Luis, None; A. Benguría Filippini, None; R. Moreno, None; M. Adrados de llano, None; H. de la Fuente, None; I. Tsukalov, None; E. Roy Vallejo, None; A. Ramiro, None; S. Iborra, None; F. Sánchez Madrid, None; A. Dopazo, None; I. Gonzalez, Gebro Pharma; S. Castañeda, Roche; E. Martín Gayo, None.