The autonomic nervous system (ANS) and the immune system are deeply interrelated. The ANS regulates both innate and adaptive immunity through the sympathetic and parasympathetic branches, and an imbalance in this system can determine an altered inflammatory response as typically observed in chronic conditions such as systemic autoimmune diseases. Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis all show a dysfunction of the ANS that is mutually related to the increase in inflammation and cardiovascular risk. Moreover, an interaction between ANS and the gut microbiota has direct effects on inflammation homeostasis. Recently vagal stimulation techniques have emerged as an unprecedented possibility to reduce ANS dysfunction, especially in chronic diseases characterized by pain and a decreased quality of life as well as in chronic inflammation.

Intestinal microbiota has been associated with systemic autoimmune diseases, yet the functional consequences of these associations are elusive. We characterized the fecal microbiota (16S rRNA gene amplification and sequencing) and the plasma metabolome (high‐performance liquid chromatography coupled to mass spectrometry) in 59 patients with systemic sclerosis (SSc) and 28 healthy controls (HCs). Microbial and metabolic data were cross‐correlated to find meaningful associations after extensive data mining analysis and internal validation. Our data show that a reduced model of nine bacteria is capable of differentiating HCs from SSc patients. SSc gut microbiota is characterized by a reduction in protective butyrate‐producing bacteria and by an increase in proinflammatory noxious genera, especially Desulfovibrio. From the metabolic point of view, a multivariate model with 17 metabolite intermediates well distinguished cases from controls. The most interesting peaks we found were identified as glycerophospholipid metabolites and benzene derivatives. The microbial and metabolic data showed significant interactions between Desulfovibrio and alpha‐N‐phenylacetyl‐l‐glutamine and 2,4‐dinitrobenzenesulfonic acid. Our data suggest that in SSc, intestinal microbiota is characterized by proinflammatory alterations subtly entwined with the metabolic state. Desulfovibrio is a relevant actor in gut dysbiosis that may promote intestinal damage and influence amino acid metabolism.

Objective In the randomised scleroderma: Cyclophosphamide Or Transplantation (SCOT trial) (NCT00114530), myeloablation, followed by haematopoietic stem cell transplantation (HSCT), led to improved clinical outcomes compared with monthly cyclophosphamide (CYC) treatment in systemic sclerosis (SSc). Herein, the study aimed to determine global molecular changes at the whole blood transcript and serum protein levels ensuing from HSCT in comparison to intravenous monthly CYC in 62 participants enrolled in the SCOT study. Methods Global transcript studies were performed at pretreatment baseline, 8 months and 26 months postrandomisation using Illumina HT-12 arrays. Levels of 102 proteins were measured in the concomitantly collected serum samples. Results At the baseline visit, interferon (IFN) and neutrophil transcript modules were upregulated and the cytotoxic/NK module was downregulated in SSc compared with unaffected controls. A paired comparison of the 26 months to the baseline samples revealed a significant decrease of the IFN and neutrophil modules and an increase in the cytotoxic/NK module in the HSCT arm while there was no significant change in the CYC control arm. Also, a composite score of correlating serum proteins with IFN and neutrophil transcript modules, as well as a multilevel analysis showed significant changes in SSc molecular signatures after HSCT while similar changes were not observed in the CYC arm. Lastly, a decline in the IFN and neutrophil modules was associated with an improvement in pulmonary forced vital capacity and an increase in the cytotoxic/NK module correlated with improvement in skin score. Conclusion HSCT contrary to conventional treatment leads to a significant ‘correction’ in disease-related molecular signatures.

The term ‘undifferentiated connective tissue disease’ (UCTD) is generally used to describe clinical entities characterised by clinical and serological manifestations of systemic autoimmune diseases but not fulfilling the criteria for defined connective tissue diseases (CTDs). In this narrative review, we summarise the results of a systematic literature research, which was performed as part of the ERN ReCONNET project, aimed at evaluating existing clinical practice guidelines (CPGs) or recommendations. No specific CPG on UCTD were found, potential areas of intervention are absence of a consensus definition of UCTD, need for specific monitoring and therapeutic protocols, stratification of UCTD based on the risk of developing a defined CTD and preventive measure for the future development of a more severe condition. Patients feel uncertainty regarding the name of the disease and feel the need of a better education and understanding of these conditions and its possible changes over time.

Objectives TYK2 is a common genetic risk factor for several autoimmune diseases. This gene encodes a protein kinase involved in interleukin 12 (IL-12) pathway, which is a well-known player in the pathogenesis of systemic sclerosis (SSc). Therefore, we aimed to assess the possible role of this locus in SSc. Methods This study comprised a total of 7103 patients with SSc and 12 220 healthy controls of European ancestry from Spain, USA, Germany, the Netherlands, Italy and the UK. Four TYK2 single-nucleotide polymorphisms (V362F (rs2304256), P1104A (rs34536443), I684S (rs12720356) and A928V (rs35018800)) were selected for follow-up based on the results of an Immunochip screening phase of the locus. Association and dependence analyses were performed by the means of logistic regression and conditional logistic regression. Meta-analyses were performed using the inverse variance method. Results Genome-wide significance level was reached for TYK2 V362F common variant in our pooled analysis (p=3.08×10⁻¹³, OR=0.83), while the association of P1104A, A928V and I684S rare and low-frequency missense variants remained significant with nominal signals (p=2.28×10⁻³, OR=0.80; p=1.27×10⁻³, OR=0.59; p=2.63×10⁻⁵, OR=0.83, respectively). Interestingly, dependence and allelic combination analyses showed that the strong association observed for V362F with SSc, corresponded to a synthetic association dependent on the effect of the three previously mentioned TYK2 missense variants. Conclusions We report for the first time the association of TYK2 with SSc and reinforce the relevance of the IL-12 pathway in SSc pathophysiology.

Prokinetics are used to treat enteric dismotility symptoms in systemic sclerosis (SSc) patients, but they often lack adequate efficacy. The most effective prokinetics belonging to the serotonin (5-HT4) receptor agonists class were withdrawn due to cardiac toxicity in relation to modest 5-HT4 receptor affinity. Prucalopride is a high-affinity 5-HT4 receptor agonist with no major cardiac issues, for which the efficacy in SSc has not yet been assessed. Forty patients with self-reported mild to moderately severe enteric symptoms were enrolled in a cross-over 2 × 2 study. Subjects were randomized 1:1 to prucalopride 2 mg/day or no treatment for one month and vice versa after a 2-week washout period. Before and after each sequence the patients compiled the University of California Los Angeles gastrointestinal tract (UCLA GIT) 2.0 questionnaire and the numbers of complete intestinal movements were recorded. Oro-cecal transit time (OCTT) was evaluated by lactulose breath test in a subgroup of patients. Data were evaluated by mixed linear models corrected for the number of laxatives used during the study periods. There were 29 subjects who completed the study; 7 subjects withdrew due to side-effects and 4 subjects were not compliant with the study procedures. As compared to dummy treatment, prucalopride was associated with more intestinal evacuations (p < 0.001), improvement of UCLA GIT constipation (-0.672 ± 0.112 vs 0.086 ± 0.115; p < 0.001), reflux (-0.409 ± 0.094 vs 0.01 ± 0.096; p < 0.005) and bloating (-0.418 ± 0.088 vs -0.084 ± 0.09; p = 0.01) scores. Treatment was ranked moderately to more than moderately effective by 22 patients (72.4%). OCTT was significantly reduced during prucalopruide consumption (prucalopride: -20.1 ± 20.1 vs no treatment: 45.8 ± 21.3 minutes; treatment effect = -65.9 minutes; p = 0.035). The safety profile of prucalopride in SSc is similar to what is known from the literature. In patients with mild to severe gastrointestinal problems, prucalopride may be effective in treating dismotility symptoms, increasing the number of complete bowel movements and improving bowel transit, reducing reflux disease and bloating. EU Clinical Trial Registry, EudraCT2012-005348-92 . Registered on 19 February 2013.