Interferon activation status underlies higher antibody response to viral antigens in patients with systemic lupus erythematosus receiving no or light treatment.

OBJECTIVES: Infections have been proposed as an environmental risk factor for autoimmune disease. Responses to microbial antigens may be studied in vivo during vaccination. We therefore followed patients with SLE and controls during split-virion influenza vaccination to quantify antibody responses against viral antigens and associated cellular and proteome parameters. METHODS: Blood samples and clinical data were collected from female patients with SLE with no or HCQ and/or low-dose prednisolone treatment (n = 29) and age- and sex-matched healthy controls (n = 17). Vaccine-specific antibody titres were measured by ELISA and IFN-induced gene expression in monocytes by quantitative PCR. Serum proteins were measured by proximity extension assay and disease-associated symptoms were followed by questionnaires. RESULTS: The vaccine-specific antibody response was significantly higher in patients compared with controls and titres of IgG targeting the viral proteins were higher in patients than controls at both 1 and 3 months after immunization. Clinical disease symptoms and autoantibody titres remained unchanged throughout the study. Notably, a positive pre-vaccination mRNA-based IFN score was associated with a significantly higher vaccine-specific antibody response and with a broader profile of autoantibody specificities. Screening of serum protein biomarkers revealed higher levels of IFN-regulated proteins in patients compared with controls and that levels of such proteins correlated with the vaccine-specific IgG response, with C-C motif chemokine ligand 3 exhibiting the strongest association. CONCLUSION: Augmented antibody responses to viral antigens develop in patients with SLE on no or light treatment and associate with markers of type I IFN system activation at the RNA and protein levels.

Viral antigens elicit augmented immune responses in primary Sjögren's syndrome.

OBJECTIVES: Infections have been suggested in the pathogenesis of primary SS (pSS). Systematic studies of immune responses to microbial antigens in vivo may be performed during vaccination. In the present study, we therefore longitudinally followed patients with pSS and controls during split-virion influenza vaccination to identify pSS-specific cellular, transcriptomic and serological responses. METHODS: Patients without treatment (pSSUntr, n = 17), on hydroxychloroquine-treatment (pSSHCQ, n = 8), and healthy controls (n = 16) were included. Antibody titres were determined by ELISA. Plasma proteins were measured by proximity extension assay. Monocyte gene expression was assessed by Nanostring. Routine laboratory tests were performed and clinical disease symptoms were registered by questionnaires. RESULTS: pSSUntr developed higher vaccine-specific IgG titres compared with controls. Notably, anti-Ro52 autoantibody titres increased in pSSUntr but remained unchanged in pSSHCQ. No changes in disease symptoms including EULAR Sjögren's Syndrome Patient Reported Index score were registered. Twenty-four hours after vaccination, the leucocyte count in pSSUntr decreased, with a concomitant increase of CCL7 in plasma. Transcriptomic analysis in monocytes revealed differential vaccination-related expression of the NEMO/IKBKG gene, and its higher induced expression in pSSUntr associated with higher serological vaccine responses. Moreover, titres of vaccine-specific antibodies were associated with higher vaccination-induced NF-κB signalling and higher steady-state IFN signatures in monocytes, and with the levels of several plasma proteins with soluble PD-1 displaying the strongest association. CONCLUSION: We observed augmented innate and adaptive immune responses in pSS following viral antigen exposure suggesting an underlying hyper-responsiveness to immune challenges, supporting a role for infections driving the immunopathology and acting as environmental risk factor for pSS.

A Non-Coding Oligonucleotide Recruits Cutaneous CD11b+ Cells that Inhibit Thelper Responses and Promote Tregs.

Skin-resident antigen-presenting cells (APC) play an important role in maintaining peripheral tolerance via immune checkpoint proteins and induction of T regulatory cells (Tregs). However, there is a lack of knowledge on how to expand or recruit immunoregulatory cutaneous cells without causing inflammation. Here, it is shown that administration of a non-coding single-stranded oligonucleotide (ssON) leads to CCR2-dependent accumulation of CD45+CD11b+Ly6C+ cells in the skin that express substantial levels of PD-L1 and ILT3. Transcriptomic analyses of skin biopsies reveal the upregulation of key immunosuppressive genes after ssON administration. Functionally, the cutaneous CD11b+ cells inhibit Th1/2/9 responses and promote the induction of CD4+FoxP3+ T-cells. In addition, ssON treatment of imiquimod-induced inflammation results in significantly reduced Th17 responses. It is also shown that induction of IL-10 production in the presence of cutaneous CD11b+ cells isolated after ssON administrations is partly PD-L1 dependent. Altogether, an immunomodulatory ssON is identified that can be used therapeutically to recruit cutaneous CD11b+ cells with the capacity to dampen Th cells.

Cigarette smoking patterns preceding primary Sjögren's syndrome.

BACKGROUND: Cigarette smoking is a well-established risk factor for several autoimmune diseases, but its role in primary Sjögren's syndrome (pSS) remains unclear. Here, we investigated the association between cigarette smoking and subsequent development of pSS. METHODS: Information on smoking habits was collected from lifestyle habit questionnaires of patients with pSS (n=815) and a matched control group (n=4425) for a case-control study. Differences in smoking exposure were analysed by conditional logistic regression. Potential interactions between smoking and risk-associated human leucocyte antigens (HLA) were assessed by multivariate regression. RESULTS: The fraction of patients with pSS having ever smoked prior to diagnosis was lower than in controls (OR 0.67, 95% CI 0.55 to 0.81). Current smoking at diagnosis was also less prevalent in cases (OR 0.37, 95% CI 0.26 to 0.53). However, period prevalence of smoking during early adulthood was not statistically different from controls (OR 0.89, 95% CI 0.66 to 1.22) but markedly decreased over time. This was partly due to patients being more prone to stop smoking, starting already 30 years prior to diagnosis (OR 2.01, 95% CI 1.22 to 3.30). Smoking patterns were also stratified by autoantibody status, yielding similar estimates. No interaction effects between HLA-DRB1 haplotypes and smoking were observed. CONCLUSION: The observed smoking patterns indicate that individuals who develop pSS smoke equally much as the general population during early life but are then more prone to stop. The data can be interpreted as smoking conferring protective effects, or reflecting early symptoms of pSS that affect smoking habits, emphasising the slow, progressive development of the disease.

Protein and DNA methylation-based scores as surrogate markers for interferon system activation in patients with primary Sjögren's syndrome.

OBJECTIVE: Standard assessment of interferon (IFN) system activity in systemic rheumatic diseases depends on the availability of RNA samples. In this study, we describe and evaluate alternative methods using plasma, serum and DNA samples, exemplified in the IFN-driven disease primary Sjögren's syndrome (pSS). METHODS: Patients with pSS seropositive or negative for anti-SSA/SSB and controls were included. Protein-based IFN (pIFN) scores were calculated from levels of PD-1, CXCL9 and CXCL10. DNA methylation-based (DNAm) IFN scores were calculated from DNAm levels at RSAD2, IFIT1 and IFI44L. Scores were compared with mRNA-based IFN scores measured by quantitative PCR (qPCR), Nanostring or RNA sequencing (RNAseq). RESULTS: mRNA-based IFN scores displayed strong correlations between B cells and monocytes (r=0.93 and 0.95, p<0.0001) and between qPCR and Nanostring measurements (r=0.92 and 0.92, p<0.0001). The pIFN score in plasma and serum was higher in patients compared with controls (p<0.0001) and correlated well with mRNA-based IFN scores (r=0.62-0.79, p<0.0001), as well as with each other (r=0.94, p<0.0001). Concordance of classification as 'high' or 'low' IFN signature between the pIFN score and mRNA-based IFN scores ranged from 79.5% to 88.6%, and the pIFN score was effective at classifying patients and controls (area under the curve, AUC=0.89-0.93, p<0.0001). The DNAm IFN score showed strong correlation to the RNAseq IFN score (r=0.84, p<0.0001) and performed well in classifying patients and controls (AUC=0.96, p<0.0001). CONCLUSIONS: We describe novel methods of assessing IFN system activity in plasma, serum or DNA samples, which may prove particularly valuable in studies where RNA samples are not available.