Search Results (181)

Background: A complex interplay between viral activity and host immune responses drives the progression of liver fibrosis in chronic hepatitis B. The T helper 17 (Th17) immune pathway, which produces the pro-inflammatory cytokine interleukin-17A (IL-17A), has been implicated in hepatic fibrogenesis. However, the relationship between IL-17A levels, IL-17A G197A (rs2275913) gene SNP, and the degree of liver fibrosis across different phases of the natural history of chronic hepatitis B remains insufficiently explored. Methods: This study employed an analytical observational design with a cross-sectional approach in treatment-naïve patients with chronic hepatitis B. The degree of liver fibrosis was assessed using liver elastography. IL-17A (rs2275913) gene SNP was analysed using Real-Time PCR, while serum IL-17A levels were measured using enzyme-linked immunosorbent assay. Statistical analyses included Spearman’s correlation, the contingency coefficient, the Chi-square test, the Kruskal–Wallis test, and the Mann–Whitney test, with a significance level set at p < 0.05. Results: A total of 76 patients with chronic hepatitis B were included in this study. The phase of disease progression was significantly associated with the degree of liver fibrosis (p = 0.016). Median IL-17A levels increased in parallel with fibrosis severity (p = 0.003), with a particularly significant association observed during the R phase (p = 0.002). However, no significant association was found between the IL-17A G197A (rs2275913) gene SNP and either liver fibrosis severity or serum IL-17A levels. Conclusions: Elevated serum IL-17A levels were associated with greater liver fibrosis severity, particularly during the reactivation phase of chronic hepatitis B. These findings suggest a potential relationship between IL-17A-mediated immune responses and liver fibrosis in patients with chronic hepatitis B. Full article

Background: Kidney transplantation is the preferred treatment for end-stage kidney disease (ESKD), but long-term outcomes remain limited by chronic allograft injury, infections, metabolic complications, and cardiovascular risk. Gut microbiota alterations and microbiota-derived metabolites may influence immune regulation, inflammation, drug metabolism, and graft outcomes through the gut–kidney axis. This review summarizes evidence on the gut microbiota in kidney transplantation, emphasizing immune tolerance, complications, cardiovascular risk, graft function, and perspectives. Methods: A structured search was conducted in PubMed, Scopus, and Web of Science to May 2026. Eligible publications included studies involving kidney transplant recipients (KTR), kidney disease or solid organ transplant populations, and mechanistic models. Evidence was synthesized narratively. Results: Gut microbiota alterations in KTR reflect pre-transplant dysbiosis and post-transplant exposures, including antibiotics, immunosuppression, infection, diet, hospitalization, and graft function. Dietary factors and nutrient-derived substrates may modulate microbial composition and production of relevant metabolites, including short-chain fatty acids (SCFAs), trimethylamine N-oxide (TMAO), tryptophan-derived compounds, bile acid derivatives, and uremic toxins. Microbiota-related pathways may involve barrier dysfunction, microbial translocation, innate immune activation, altered regulatory T cell/T helper 17 (Treg/Th17) balance, metabolite signaling, uremic toxin generation, and endothelial stress. Clinical studies associate dysbiosis and microbial metabolites with diarrhea, infections, delayed graft function (DGF), rejection-related shifts, tacrolimus variability, cardiovascular risk, graft dysfunction, graft failure, and mortality. Most findings need validation. Conclusions: Gut microbiota signatures and microbial metabolites are promising markers of transplant-related risk, but not established causal determinants or therapeutic targets. Clinical translation requires standardized methods, multi-omics integration, and prospective patient- and graft-centered trials. Full article

Background/Objectives: Lactobacillus rhamnosus GG (LGG) is one of the most widely utilized probiotic strains with a variety of biological functions including prevention and treatment of gastro-intestinal infections and regulation of immune responses. Methods: Here, we explored the role of LGG in regulating the differentiation of naïve CD4⁺ T cells and its effect on alleviating the dextran sulfate sodium (DSS)-induced colitis in mice. Results: In vitro, we showed that LGG-derived metabolites not only promoted the differentiation of naive CD4⁺ T cells into T-helper 17 cells (Th17 cells), but also selectively upregulated the expression of lactate-specific transporter solute carrier family 5 member 12 (SLC5A12). Interestingly, we manipulated a CD4⁺ T cell-monocytes co-culture and found that heated LGG-loaded monocytes modulate naive CD4⁺ T cells to differentiate preferentially into Treg cells rather than Th17 cells. To explain the above-mentioned contradiction, we used an experimental colitis model and found that LGG administration alleviated the DSS-induced colitis in mice, as indicated by decreases in weight loss and disease activity index. Moreover, SLC5A12 blockade (using a specific antibody) further reduced the colonic histological inflammatory score and decreased secretion of proinflammatory cytokines such as IFN-γ, IL-6, IL-17F, and IL-21. Notably, SLC5A12 blockade abolished the LGG-induced differentiation of the IL-17⁺CD4⁺ T (Th17) cells but significantly increased the frequency of Foxp3⁺CD4⁺ T (Treg) cells in the colonic lamina propria. Furthermore, a higher intracellular lactate concentration was observed in the colonic CD4⁺ T cells isolated from the LGG-treated colitic mice compared with other groups. Additionally, we also found elevated levels of oxidative stress indicators such as MDA and H₂O₂, as well as excessive reactive oxygen species (ROS) in colonic tissue of DSS-treated only mice, while LGG can scavenge ROS by inducing nuclear factor-erythroid 2-related factor 2 (Nrf2) expression in enterocytes. Conclusions: Altogether, these results indicate that LGG might alleviate preclinical colitis by modulating the Th17/Treg balance, and SLC5A12 blockade appears to enhance the anti-inflammatory properties of LGG. Full article

Pertussis is a highly contagious respiratory infection caused by Bordetella pertussis and remains a persistent global health challenge despite widespread vaccination. This review aims to analyze the immune pathogenesis of B. pertussis infection and to identify key immunological limitations of current acellular pertussis vaccines that contribute to ongoing transmission. A narrative review of the literature was conducted, focusing on mechanisms of host–pathogen interaction, immune evasion, and vaccine-induced immunity. Evidence indicates that although acellular vaccines effectively reduce disease severity, they fail to prevent nasopharyngeal colonization and transmission, largely due to insufficient induction of mucosal immunity, T helper 1 (Th1) and T helper 17 (Th17) responses, and airway tissue-resident memory T cells. In contrast, natural infection induces broader immune responses, including secretory IgA production and robust cellular immunity, which are associated with improved bacterial clearance. Emerging next-generation vaccine strategies, including mucosal, outer membrane vesicle-based, and live-attenuated platforms, demonstrate enhanced ability to reduce bacterial colonization in preclinical and clinical models. In conclusion, effective control of pertussis transmission will require vaccine approaches that replicate infection-induced immunity at the respiratory mucosa, emphasizing the need for redesigned immunization strategies. Full article

Lyme disease (LD) is classically defined as a tick-borne infection caused by Borrelia burgdorferi sensu lato (Bbsl). However, accumulating evidence indicates that, beyond microbial persistence, Bbsl infection can initiate sustained immune dysregulation and post-infectious inflammatory phenotypes in a subset of patients. This narrative review integrates open-access experimental, translational, and clinical data and discusses LD within the spectrum of infection-triggered, immune-mediated processes. We review key immunopathogenic mechanisms, including dysregulated innate immune activation, type I interferon (IFN-I) signaling, T helper 1 and T helper 17 (Th1/Th17) polarization with regulatory T-cell (Treg) insufficiency, antigen persistence (notably borrelial peptidoglycan), and pathways linking infection to autoimmunity such as molecular mimicry, epitope spreading, and human leukocyte antigen (HLA)-restricted susceptibility. These mechanisms are integrated with immune-mediated clinical manifestations affecting the central nervous system (CNS), peripheral nervous system (PNS), musculoskeletal system, heart, skin, and hematologic compartment. Finally, we discuss translational implications for diagnosis, biomarker-guided stratification, and emerging therapeutic strategies that extend beyond antimicrobial therapy, while addressing current controversies and limitations. This framework supports a mechanistic model in which Lyme disease-associated morbidity in selected patients reflects persistent immune activation and dysregulated host responses triggered by infection. Full article

Temporomandibular disorders (TMDs) are multifactorial conditions traditionally attributed to excessive mechanical loading on the temporomandibular joint, leading to clinical manifestations ranging from joint sounds to structural deformation. Contributing factors include trauma, occlusal abnormalities, psychological stress, and bruxism. However, immune and molecular alterations associated with early disease activity are not systematically integrated into structure-centered TMD frameworks. Emerging evidence indicates that temporomandibular joint osteoarthritis (TMJOA) involves activation of innate immunity caused by damage-associated molecular patterns (DAMPs) generated through mechanical loading, together with non-antigen-specific adaptive immune responses, including macrophage polarization and T helper 17 (Th17) and regulatory T (Treg) cell imbalance. Inflammatory and mechanical inputs converge through shared signaling modules and mechanoresponsive transcriptional programs, promoting extracellular matrix degradation, fibrotic remodeling, and subchondral bone remodeling. This review synthesizes the current immunopathological and mechanobiological evidence and introduces temporomandibular immunologic disease (TMID) as a mechanism-oriented framework, characterized by a reinforcing cycle between mechanically induced tissue damage and immune activation within the temporomandibular joint (TMJ) microenvironment. TMID complements TMJOA and Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) structural diagnostic categories while excluding antigen-specific autoimmune arthritides such as rheumatoid arthritis, thus functioning as a mechanistic overlay framework for the integration of immuno-mechanical signaling networks in immune-active, mechanically driven TMJ pathology. Full article

Plaque psoriasis (PP) is a chronic immune-mediated skin disorder characterized by T-cell dysregulation and an imbalance between regulatory T cells (Treg) and T helper 17 (Th17) cells. Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), a key inhibitory checkpoint molecule expressed on Treg cells, and its soluble isoform (sCTLA-4) are critical regulators of peripheral immune tolerance and may contribute to PP pathogenesis. This case–control study evaluated the association between the +49 A>G variant of the CTLA4 gene (rs231775) and susceptibility to PP in a mestizo population from western Mexico and assessed serum sCTLA-4 levels. A total of 204 patients with PP and 214 control subjects (CS) were genotyped using PCR-RFLP, and sCTLA-4 concentrations were measured by ELISA. The AG genotype was the most frequent in both groups (49% in PP and 53% in CS), with no significant differences in genotype or allele distributions. Serum sCTLA-4 levels were significantly higher in CS compared to patients (p < 0.05), and no genotype-dependent differences were observed. The rs231775 variant was not associated with PP susceptibility in this population. However, reduced circulating sCTLA-4 levels in patients suggest impaired CTLA-4-mediated immune regulation independent of this variant. Full article

Polycystic ovary syndrome (PCOS) is associated with reproductive, metabolic, and inflammatory disturbances. Alterations in T-cell subpopulations—particularly increased T helper 17 cells (Th17) and decreased regulatory T cells (Treg)—have been reported in PCOS; however, data on normoandrogenic phenotype D remain limited. Hypoxia-inducible factor 1α (HIF-1α), a key regulator of hypoxic response, also influences immune and metabolic processes and may affect the Treg/Th17 balance. To assess Treg and Th17 abundance, HIF-1α expression within these cells, and their ratios in women with phenotype D PCOS compared with healthy controls. The study included 49 women with phenotype D PCOS and 40 controls comparable in terms of age and BMI. Anthropometric, hormonal, metabolic, and inflammatory parameters were evaluated. Peripheral T-cell subsets and intracellular HIF-1α expression were analyzed by multiparameter flow cytometry. Absolute numbers of Treg and Th17 cells did not differ between groups. However, PCOS patients showed significantly higher Treg/Th17 and HIF-1α-positive Treg/HIF-1α-positive Th17 ratios. HIF-1α-positive Treg cells correlated positively with adiposity and insulin resistance markers; however, after False Discovery Rate (FDR) correction, correlations no longer remained statistically significant. Despite normoandrogenemia, PCOS patients exhibited higher hs-CRP levels. Phenotype D PCOS is characterized by altered immune cell ratios rather than absolute T-cell differences, suggesting distinct immunological features and persistent low-grade inflammation. Full article

Lipid A is a component of lipopolysaccharide (LPS) of Gram-negative bacteria. Previously, we demonstrated that synthesized lipid A derived from Alcaligenes faecalis (ALA) could enhance antigen-specific immunoglobulin (Ig) A and T helper (Th) 17 responses, when ALA was co-administered experimentally with an antigen as a vaccine adjuvant. This raised concerns about the safety of the ALA usage, since IgA and Th17 responses have been suggested to play a pathogenic role in several immune-mediated diseases, including multiple sclerosis (MS). We investigated whether ALA administrations could exacerbate an animal model of MS, Theiler’s murine encephalomyelitis virus (TMEV) infection. TMEV-infected SJL/J mice were administered ALA at various time points, and their neurological signs were observed for 7 weeks. We found that ALA administrations did not exacerbate TMEV-induced inflammatory disease or viral persistence in the central nervous system (CNS), clinically or histologically. Furthermore, ALA administrations did not enhance TMEV-specific humoral and cellular responses, including IgA and Th17 responses. On the other hand, principal component analysis (PCA) of the fecal, not the ileal, samples showed significant changes in the microbiota, characterized by increases in the relative abundance of bacteria belonging to the phylum Bacteroidota, including the genera Alistipes and Bacteroides. Therefore, ALA injections could be safe for use in immune-mediated diseases, whose immunopathology has been associated with IgA and Th17 responses. Full article

Background: Sarcoidosis is a systemic granulomatous disease of unknown etiology. Pulmonary sarcoidosis with extrapulmonary lesions (EPL) confers poor prognoses. The transcriptomic features of peripheral blood mononuclear cells (PBMCs) could be crucial in sarcoidosis pathogenesis. However, the gene expression characteristics associated with EPL development remain unknown. Methods: Bulk PBMCs were collected from 26 healthy controls and 14 patients with pulmonary sarcoidosis stratified into those with (n = 9) or without (n = 5) EPL. None of the participants were receiving immunosuppressive agents. PBMC transcriptomic analysis was conducted using RNA sequencing. Results: Principal component analysis (PCA) revealed a clear distinction between pulmonary sarcoidosis and healthy control groups, with 227 differentially expressed genes (88 upregulated, 139 downregulated), including upregulated (CLEC7A, GBP5, JAK2, IL15, IL1B, CXCL8, and CXCL10) and downregulated (TNFRSF13C, CD40LG, CD28, and ID3) genes in pulmonary sarcoidosis group. Enrichment analysis revealed upregulated immunological pathways related to granuloma formation in pulmonary sarcoidosis PBMCs, including T helper 17 and tumor necrosis factor-alpha signaling pathways, IL-1B, IL-6, and IL-17 production, and response to external stimuli. Furthermore, patients with and without EPL showed 206 differentially expressed genes (131 upregulated, 75 downregulated), including upregulated (IFNG and IFNLR1) and downregulated (SOCS3, MMP9, and CXCL10) genes. Gene ontology (GO) analysis revealed that interleukin 6 (IL-6) and IL-23 production were upregulated in patients with EPL. Conclusions: These findings elucidate the mechanisms underlying granuloma formation in sarcoidosis and demonstrate the differential transcriptomic features of PBMCs in patients with and without EPL. The upregulation of IFNG and IFNLR1 may be related to EPL development and could serve as potential therapeutic targets for sarcoidosis. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disorder associated with immune dysregulation, skin barrier dysfunction, and microbial dysbiosis characterized by Staphylococcus aureus overcolonization and reduced bacterial diversity. Beyond its classical role in calcium homeostasis, Vitamin D (VD) influences skin immunity and microbial composition. This review summarizes current knowledge on VD metabolism, its immunological pathways in AD, and its interactions with the skin microbiome. Recent evidence positions the skin as an active immunological organ rather than a passive barrier. Commensal bacteria such as Staphylococcus epidermidis not only inhibit pathogens by producing bacteriocins and modulins but also generate ceramides and short-chain fatty acids (SCFAs) that stabilize the lipid barrier. Moreover, dermal fibroblasts and preadipocytes produce antimicrobial peptides, while resident γδ T cells release growth factors like fibroblast growth factor 7 (FGF7), linking host defense with tissue regeneration. VD modulates AD by suppressing T helper 2 cells/T helper 17 cell responses, enhancing regulatory T cell development, inducing antimicrobial peptides, and strengthening skin and gut barrier integrity. Its interaction with the microbiome and pathways such as SCFA and aryl hydrocarbon receptor (AhR) signaling supports its potential as an adjunctive therapy in AD management. Evidence from mechanistic studies and animal models suggests that VD supplementation may modulate inflammation and microbial diversity. Clinical implications, therapeutic perspectives, and future research directions highlight the potential of VD as a therapeutic adjunct in AD management. Full article

Alcohol-associated liver disease is a global health burden with high morbidity and mortality, and the fungal microbiome is important for its progression. In particular, Candida albicans and C. albicans-reactive T helper 17 (Th17) cells contribute to alcohol-associated liver disease. Specific C. albicans antigens that activate Th17 cells during this disease are unknown. The C. albicans 65 kDa mannoprotein (CaMp65p) is one of the most abundant and immunodominant proteins of C. albicans, and is capable of eliciting robust T cell and interleukin (IL)-17A responses. The aim of this study was to measure levels of CaMp65p in serum of patients with alcohol use disorder and liver disease. Serum CaMp65p levels were measured in the serum of 60 patients with alcohol use disorder using an indirect competitive Enzyme-Linked Immunoabsorbent Assay (ELISA). Serum CaMp65p levels were correlated with liver disease severity. Serum CaMp65p levels positively correlated with several clinical and biochemical markers of liver injury and disease within the patient group with alcohol use disorder, including serum aspartate aminotransferase (AST; R = 0.33, p = 0.0092), alanine aminotransferase (ALT; R = 0.27, p = 0.037), gamma-glutamyl transferase (GGT; R = 0.35, p = 0.0055) and alkaline phosphatase (R = 0.36, p = 0.0052), and with the circulating M65 fragment of cytokeratin 18 (CK18-M65; R = 0.51, p = 0.0012), a marker of hepatocyte death. In addition, patients with alcohol use disorder in the upper quartile had significantly higher liver stiffness (p = 0.0022). Serum CaMp65p was significantly higher in patients with fibrosis stage F2–F4 as compared with patients with no or minimal fibrosis F0–F1 (p = 0.0082). The area under the curve (AUC) for detecting F2–F4 fibrosis was 0.70. Elevated serum CaMp65p levels are associated not only with more severe hepatic injury, but also with liver fibrosis in patients with alcohol use disorder. Therefore, CaMp65p may serve as a non-invasive biomarker for fibrosis assessment in patients with alcohol use disorder. Full article

Psoriasis is a chronic inflammatory skin disease driven by genetic, environmental, and immune factors. While biologics like adalimumab (anti-TNFα) and risankizumab (anti-IL-23) have improved outcomes, patient response variability remains unclear. This study examined immune-related transcriptomic differences between lesional (L) and non-lesional (NL) psoriatic skin, focusing on immune-related hub genes, their plasma levels, and their correlations with severity and treatment response. Patients with moderate-to-severe psoriasis were enrolled before treatment with anti-TNFα (n = 16) or anti-IL-23 (n = 18). Plasma and paired L and NL skin biopsies were collected for RNA sequencing. Gene ontology enrichment analysis found four immune-related terms enriched in L skin: T-helper 17, granulocyte and lymphocyte chemotaxis, and antimicrobial humoral response. A protein–protein interaction network identified ten immune-related hub genes upregulated in L skin that correlated with clinical severity. Patients with prior treatments expressed distinctive gene profiles. Plasma levels of CCL20 strongly correlated with disease severity. Decision tree models identified CCL20 expression in skin and plasma levels of IL-6 and CXCL8 as candidate predictors for anti-TNFα response. Similarly, skin expression of CXCL8, IL-6, and CXCL10, alongside plasma levels of CCL20, IL-6, and CXCL8, may predict anti-IL-23 response. Ten immune-related hubs may serve as possible biomarkers for disease severity and therapeutic response in psoriasis. Full article

Background: While most Escherichia coli strains are harmless members of the gastrointestinal microbiota, certain pathogenic variants can cause severe intestinal and extraintestinal diseases. A notable outbreak of E. coli O104:H4, involving both enteroaggregative (EAEC) and enterohemorrhagic (EHEC) strains, occurred in Europe, resulting in symptoms ranging from bloody diarrhea to life-threatening colitis and hemolytic uremic syndrome (HUS). Since treatment options remain limited and have changed little over the past 40 years, there is an urgent need for an effective vaccine. Such a vaccine would offer major public health and economic benefits by preventing severe infections and reducing outbreak-related costs. A multiepitope vaccine approach, enabled by advances in immunoinformatics, offers a promising strategy for targeting HUS-causing E. coli (O104:H4 and O157:H7 serotypes) with minimal disruption to normal microbiota. This study aimed to design an immunogenic multiepitope vaccine (MEV) construct using bioinformatics and immunoinformatic tools. Methods and Results: Comparative proteomic analysis identified 672 proteins unique to E. coli O104:H4, excluding proteins shared with the nonpathogenic E. coli K-12-MG1655 strain and those shorter than 100 amino acids. Subcellular localization (P-SORTb) identified 17 extracellular or outer membrane proteins. Four proteins were selected as vaccine candidates based on transmembrane domains (TMHMM), antigenicity (VaxiJen), and conservation among EHEC strains. Epitope prediction revealed ten B-cell, four cytotoxic T-cell, and three helper T-cell epitopes. Four MEVs with different adjuvants were designed and assessed for solubility, stability, and antigenicity. Structural refinement (GALAXY) and docking studies confirmed strong interaction with Toll-Like Receptor 4 (TLR4). In silico immune simulations (C-ImmSim) indicated robust humoral and cellular immune responses. In Conclusions, the proposed MEV construct demonstrated promising immunogenicity and warrants further validation in experimental models. Full article

Respiratory syncytial virus (RSV) remains a leading cause of acute lower respiratory tract infections globally, particularly affecting infants, older adults, and immunocompromised individuals. While recent advances in prophylaxis, such as long-acting monoclonal antibodies and maternal immunization, offer promise for prevention, therapeutic options for active infection remain limited. Severe RSV disease is often driven not solely by viral replication but by dysregulated host immune responses, including excessive cytokine production, T helper type 2 (Th2) and T helper type 17 (Th17) cell polarization, and impaired interferon signaling. RSV has evolved sophisticated immune evasion strategies, such as inhibition of dendritic cell maturation, degradation of signal transducer and activator of transcription 2 (STAT2) via nonstructural proteins 1 and 2 (NS1/NS2), and interference with pattern recognition receptor signaling, particularly Toll-like receptors (TLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors. These mechanisms result in attenuated innate immune responses and defective adaptive immunity, contributing to viral persistence, immunopathology, and recurrent infections. Moreover, age-dependent vulnerabilities, such as immune immaturity in infants and immunosenescence in older adults, exacerbate disease severity. Excessive immune activation leads to bronchiolitis, airway remodeling, and long-term sequelae including wheezing and asthma. Emerging immunomodulatory therapies aim to restore immune balance, targeting cytokines (e.g., interleukin-6 [IL-6], interleukin-1 beta [IL-1β]), the Janus kinase–signal transducer and activator of the transcription (JAK-STAT) pathway, or inflammasome activity. Host-directed therapies and direct-acting antivirals are also under investigation. A better understanding of RSV–host immune interactions is critical for optimizing therapeutic strategies and designing effective vaccines. This review synthesizes current knowledge on RSV immunopathogenesis and highlights immunomodulation as a promising frontier for therapeutic intervention. Full article