Expression of CD1a protein defines a human dendritic cell (DC) subset with unique functional activities. We aimed to study the expression of the Nav1.7 sodium channel and the functional consequences of its activity in CD1a⁻ and CD1a⁺ DC. Single-cell electrophysiology (patch-clamp) and quantitative PCR experiments performed on sorted CD1a⁻ and CD1a⁺ immature DC (IDC) showed that the frequency of cells expressing Na⁺ current, current density, and the relative expression of the SCN9A gene encoding Nav1.7 were significantly higher in CD1a⁺ cells than in their CD1a⁻ counterparts. The activity of Nav1.7 results in a depolarized resting membrane potential (−8.7 ± 1.5 mV) in CD1a⁺ IDC as compared with CD1a⁻ cells lacking Nav1.7 (−47 ± 6.2 mV). Stimulation of DC by inflammatory signals or by increased intracellular Ca²⁺ levels resulted in reduced Nav1.7 expression. Silencing of the SCN9A gene shifted the membrane potential to a hyperpolarizing direction in CD1a⁺ IDC, resulting in decreased cell migration, whereas pharmacological inhibition of Nav1.7 by tetrodotoxin sensitized the cells for activation signals. Fine-tuning of IDC functions by a voltage-gated sodium channel emerges as a new regulatory mechanism modulating the migration and cytokine responses of these DC subsets.

The consumption of artificial and low-calorie sweeteners (ASs, LCSs) is an important component of the Western diet. ASs play a role in the pathogenesis of metabolic syndrome, dysbiosis, inflammatory bowel diseases (IBDs), and various inflammatory conditions. Intestinal nutrient-sensing receptors act as a crosstalk between dietary components, the gut microbiota, and the regulation of immune, endocrinological, and neurological responses. This narrative review aimed to summarize the possible effects of ASs and LCSs on intestinal nutrient-sensing receptors and their related functions. Based on the findings of various studies, long-term AS consumption has effects on the gut microbiota and intestinal nutrient-sensing receptors in modulating incretin hormones, antimicrobial peptides, and cytokine secretion. These effects contribute to the regulation of glucose metabolism, ion transport, gut permeability, and inflammation and modulate the gut–brain, and gut–kidney axes. Based on the conflicting findings of several in vitro, in vivo, and randomized and controlled studies, artificial sweeteners may have a role in the pathogenesis of IBDs, functional bowel diseases, metabolic syndrome, and cancers via the modulation of nutrient-sensing receptors. Further studies are needed to explore the exact mechanisms underlying their effects to decide the risk/benefit ratio of sugar intake reduction via AS and LCS consumption.

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that sense lipophilic molecules and act as transcription factors to regulate target genes. PPARs have been implicated in the regulation of innate immunity, glucose and lipid metabolism, cell proliferation, wound healing, and fibrotic processes. Some synthetic PPAR ligands are promising molecules for the treatment of inflammatory and fibrotic processes in immune-mediated intestinal diseases. Some of these are currently undergoing or have previously undergone clinical trials. Dietary PPAR ligands and changes in microbiota composition could modulate PPARs’ activation to reduce inflammatory responses in these immune-mediated diseases, based on animal models and clinical trials. This narrative review aims to summarize the role of PPARs in immune-mediated bowel diseases and their potential therapeutic use.

Background: The outcome of rheumatoid arthritis (RA) should be determined early. Rapid radiological progression (RRP) is > or = 5 units increase according to the van der Heijde-Sharp score within a year. The risk of RRP can be estimated by a matrix model using non-radiographic indicators, such as C-reactive protein (CRP), rheumatoid factor (RF) and swollen joint count (SJC). Patients and methods: A non-interventional, cross-sectional, retrospective study was conducted in eleven Hungarian arthritis centres. We assessed RRP risk in biologic-naïve RA patients with the prevalence of high RRP risk as primary endpoint. RRP was calculated according to this matrix model. As a secondary endpoint, we compared RRP in methotrexate (MTX) responders vs non-responders. Results: We analyzed data from 1356 patients. Mean CRP was 17.7 mg/l, RF was 139.3 IU/ml, mean 28-joint disease activity score (DAS28) was 5.00 and mean SJC was 6.56. Altogether 18.2% of patients had high risk (≥40%) of RRP. RA patients with high RRP risk of RRP (n = 247) had significantly lower age compared to those with RRP < 40% (n = 1109). MTX non-response (OR: 16.84), male gender (OR: 1.67), erosions at baseline (OR: 1.50) and ACPA seropositivity (OR: 2.18) were independent predictors of high-risk RRP. Male gender (OR: 5.20), ACPA seropositivity (OR: 4.67) and erosions (OR: 7.98) were independent predictors of high RRP risk in MTX responders. Conclusions: In this Hungarian study, high RRP risk occurred in 18% of RA patients. These patients differ from others in various parameters. RRP was associated with non-response to MTX.

Autoimmune and immune-mediated inflammatory diseases (IMIDs) develop when genetically and environmentally susceptible hosts lose stable immune tolerance. The gut ecosystem is increasingly recognized as a biologically active interface in this process. Its bacterial, fungal, and viral components may shape mucosal and systemic immunity through antigenic stimulation, barrier regulation, and metabolite-dependent signaling, although the strength of evidence is uneven: bacteriome data are currently the most mature, whereas mycobiome, virome, and phageome findings remain more disease-specific and emerging. Dysbiosis may influence autoimmunity through overlapping routes, including epithelial barrier failure, altered short-chain fatty acid, bile acid, and tryptophan metabolism, molecular mimicry, and cross-kingdom microbial interactions. Nutrition is central to this network because dietary substrates determine microbial growth, metabolic output, epithelial integrity, and immune-cell differentiation. In this narrative review, we integrate evidence on disease-associated bacteriome, mycobiome, and virome patterns in systemic autoimmune diseases, with emphasis on rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, systemic sclerosis, spondyloarthritis, vasculitides, and idiopathic inflammatory myopathies. COVID-19 is considered not as a proven causal driver of autoimmunity, but as an example of an environmental and infectious insult capable of perturbing microbiome–barrier–immune communication. Finally, we discuss diet-based and microbiome-targeted approaches, including probiotics, prebiotics, synbiotics, and postbiotics, as adjunctive strategies that may help restore microbial resilience and immune balance. A better understanding of the diet–microbiome–host immunity axis may support more personalized preventive and therapeutic concepts in autoimmune disease.

Immune-mediated inflammatory diseases (IMIDs) arise from interactions among genetic susceptibility, epithelial barrier function, microbiota, diet, and other environmental exposures. Modern diets influence mucosal immunity not only through fibre intake, food processing, and microbiota composition, but also through a less explored exposure layer: plant-derived molecules with potential immune activity. Crop breeding, intensive agriculture, global trade, gluten-free substitutes, and plant-based food technologies have changed the spectrum, dose, concentration, and matrix in which plant defence proteins, antinutritional factors, endogenous toxicants, and novel plant antigens reach the intestinal surface. In this structured, hypothesis-generating narrative review, we propose dietary adjuvanticity as a mechanistic framework for considering how selected food-derived molecules may amplify mucosal immune responsiveness, modify antigen presentation, disturb barrier function, or lower tolerance thresholds without necessarily acting as classical autoantigens. The framework differs from general food-derived immunomodulation, nutritional exposomics, and diet-microbiota-host interaction models by focusing specifically on adjuvant-like immune amplification at the intestinal mucosa. The ASIA concept is used only in Shoenfeld’s functional sense, as an analogy for exogenous immune amplification through innate activation, danger signalling, bystander activation, epitope spreading, and loss of tolerance in susceptible hosts; it is not applied as a dietary diagnosis. Wheat amylase-trypsin inhibitors, gluten epitopes, lectins, potato glycoalkaloids, saponins, quinoa prolamins, emerging legume proteins, L-canavanine, and tolerance-promoting plant substrates are discussed with explicit separation of established clinical evidence, strong mechanistic evidence, preclinical/ex vivo evidence, and speculative disease-modifier hypotheses. Overall, plant-derived exposures are best interpreted as potential modifiers within the IMID exposome, not as primary causes of autoimmunity. Testing this model will require defined exposures, food-matrix and processing studies, biomarkers of barrier and immune activation, patient stratification, and controlled human studies.