Tbet Deficiency Causes T Helper Cell Dependent Airways Eosinophilia and Mucus Hypersecretion in Response to Rhinovirus Infection

Integrated nasopharyngeal airway metagenome and asthma genetic risk endotyping of severe bronchiolitis in infancy and risk of childhood asthma

BACKGROUND

Infants with bronchiolitis are at increased risk of developing asthma. Growing evidence suggests bronchiolitis is a heterogeneous condition. However, little is known about its biologically distinct subgroups based on the integrated metagenome and asthma genetic risk signature and their longitudinal relationships with asthma development.

METHODS

In a multicentre prospective cohort study of infants with severe bronchiolitis (i.e. bronchiolitis requiring hospitalisation), we profiled nasopharyngeal airway metagenome and virus at hospitalisation, and calculated the polygenic risk score of asthma. Using similarity network fusion clustering approach, we identified integrated metagenome-asthma genetic risk endotypes. In addition, we examined their longitudinal association with the risk of developing asthma by the age of 6 years.

RESULTS

Out of 450 infants with bronchiolitis (median age 3 months), we identified five distinct endotypes, characterised by their nasopharyngeal metagenome, virus and asthma genetic risk profiles. Compared with endotype A infants (who clinically resembled "classic" bronchiolitis), endotype E infants (characterised by a high abundance of Haemophilus influenzae, high proportion of rhinovirus (RV)-A and RV-C infections and high asthma genetic risk) had a significantly higher risk of developing asthma (16.7% versus 35.9%; adjusted OR 2.24, 95% CI 1.02-4.97; p=0.046). The pathway analysis showed that endotype E had enriched microbial pathways (e.g. glycolysis, l-lysine, arginine metabolism) and host pathways (e.g. interferons, interleukin-6/Janus kinase/signal transducers and activators of transcription-3, fatty acids, major histocompatibility complex and immunoglobin-related) (false discovery rate (FDR)<0.05). Additionally, endotype E had a significantly higher proportion of neutrophils (FDR<0.05).

CONCLUSION

In this multicentre prospective cohort study of infant bronchiolitis, the clustering analysis of integrated-omics data identified biologically distinct endotypes with differential risks of developing asthma.

Long-acting anti-inflammatory injectable DEX-Gel with sustained release and self-healing properties regulates TH1/TH2 immune balance for minimally invasive treatment of allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a prevalent immune-related allergic disease, and corticosteroid nasal sprays serve as the primary treatment for this patient population. However, their short duration of efficacy and frequent administration pose challenges, leading to drug wastage and potential adverse effects. To overcome these limitations, we devised a novel approach to formulate DEX-Gel by incorporating dexamethasone (DEX) into a blend of Pluronic F127, stearic acid (SA), and polyethylene glycol 400 (PEG400) to achieve sustained-release treatment for AR.

RESULTS

Following endoscopic injection into the nasal mucosa of AR rats, DEX-Gel exhibited sustained release over a 14-day period. In vivo trials employing various assays, such as flow cytometry (FC), demonstrated that DEX-Gel not only effectively managed allergic symptoms but also significantly downregulated helper T-cells (TH) 2 and TH2-type inflammatory cytokines (e.g., interleukins 4, 5, and 13). Additionally, the TH1/TH2 cell ratio was increased.

CONCLUSION

This innovative long-acting anti-inflammatory sustained-release therapy addresses the TH1/TH2 immune imbalance, offering a promising and valuable approach for the treatment of AR and other inflammatory nasal diseases.

Artemisia gmelinii Extract Alleviates Allergic Airway Inflammation via Balancing TH1/TH2 Homeostasis and Inhibiting Mast Cell Degranulation

A new terminology "combined allergic rhinitis and asthma syndrome (CARAS)" was introduced to describe patients suffering from both allergic rhinitis (AR) and asthma. The pathogenesis of allergic airway inflammation has been well known, with the main contribution of TH1/TH2 imbalance and mast cell degranulation. Artemisia gmelinii has been used as an herbal medicine with its hepaprotective, anti-inflammatory, and antioxidant properties. In this study, the effect of A. gmelinii extracts (AGE) on the ovalbumin (OVA)-induced CARAS mouse model was investigated. AGE administration significantly alleviated the nasal rubbing and sneezing, markedly down-regulated both OVA-specific IgE, IgG₁, and histamine levels, and up-regulated OVA-specific IgG_2a in serum. The altered histology of nasal and lung tissues of CARAS mice was effectively ameliorated by AGE. The AGE treatment group showed markedly increased levels of the TH1 cytokine interleukin (IL)-12 and TH1 transcription factor T-bet. In contrast, the levels of the TH2 cytokines, including IL-4, IL-5, IL-13, and the TH2 transcription factor GATA-3, were notably suppressed by AGE. Moreover, AGE effectively prevented mast cell degranulation in vitro and mast cell infiltration in lung tissues in vivo. Based on these results, we suggest that AGE could be a potential therapeutic agent in OVA-induced CARAS by virtue of its role in balancing the TH1/TH2 homeostasis and inhibiting the mast cell degranulation.

Corticosteroid insensitivity persists in the absence of STAT1 signaling in severe allergic airway inflammation

Corticosteroid insensitivity in asthma limits the ability to effectively manage severe asthma, which is characterized by persistent airway inflammation, airway hyperresponsiveness (AHR), and airflow obstruction despite corticosteroid treatment. Recent reports indicate that corticosteroid insensitivity is associated with increased interferon-γ (IFN-γ) levels and T-helper (Th) 1 lymphocyte infiltration in severe asthma. Signal transducer and activator of transcription 1 (STAT1) activation by IFN-γ is a key signaling pathway in Th1 inflammation; however, its role in the context of severe allergic airway inflammation and corticosteroid sensitivity remains unclear. In this study, we challenged wild-type (WT) and Stat1^-/- mice with mixed allergens (MA) augmented with c-di-GMP [bis-(3'-5')-cyclic dimeric guanosine monophosphate], an inducer of Th1 cell infiltration with increased eosinophils, neutrophils, Th1, Th2, and Th17 cells. Compared with WT mice, Stat1^-/- had reduced neutrophils, Th1, and Th17 cell infiltration. To evaluate corticosteroid sensitivity, mice were treated with either vehicle, 1 or 3 mg/kg fluticasone propionate (FP). Corticosteroids significantly reduced eosinophil infiltration and cytokine levels in both c-di-GMP + MA-challenged WT and Stat1^-/- mice. However, histological and functional analyses show that corticosteroids did not reduce airway inflammation, epithelial mucous cell abundance, airway smooth muscle mass, and AHR in c-di-GMP + MA-challenged WT or Stat1^-/- mice. Collectively, our data suggest that increased Th1 inflammation is associated with a decrease in corticosteroid sensitivity. However, increased airway pathology and AHR persist in the absence of STAT1 indicate corticosteroid insensitivity in structural airway cells is a STAT1 independent process.

High Th2 cytokine levels and upper airway inflammation in human inherited T-bet deficiency

We have described a child suffering from Mendelian susceptibility to mycobacterial disease (MSMD) due to autosomal recessive, complete T-bet deficiency, which impairs IFN-γ production by innate and innate-like adaptive, but not mycobacterial-reactive purely adaptive, lymphocytes. Here, we explore the persistent upper airway inflammation (UAI) and blood eosinophilia of this patient. Unlike wild-type (WT) T-bet, the mutant form of T-bet from this patient did not inhibit the production of Th2 cytokines, including IL-4, IL-5, IL-9, and IL-13, when overexpressed in T helper 2 (Th2) cells. Moreover, Herpesvirus saimiri-immortalized T cells from the patient produced abnormally large amounts of Th2 cytokines, and the patient had markedly high plasma IL-5 and IL-13 concentrations. Finally, the patient's CD4+ αβ T cells produced most of the Th2 cytokines in response to chronic stimulation, regardless of their antigen specificities, a phenotype reversed by the expression of WT T-bet. T-bet deficiency thus underlies the excessive production of Th2 cytokines, particularly IL-5 and IL-13, by CD4+ αβ T cells, causing blood eosinophilia and UAI. The MSMD of this patient results from defective IFN-γ production by innate and innate-like adaptive lymphocytes, whereas the UAI and eosinophilia result from excessive Th2 cytokine production by adaptive CD4+ αβ T lymphocytes.

Rhinovirus C Infection Induces Type 2 Innate Lymphoid Cell Expansion and Eosinophilic Airway Inflammation

Rhinovirus C (RV-C) infection is associated with severe asthma exacerbations. Since type 2 inflammation is an important disease mechanism in asthma, we hypothesized that RV-C infection, in contrast to RV-A, preferentially stimulates type 2 inflammation, leading to exacerbated eosinophilic inflammation. To test this, we developed a mouse model of RV-C15 airways disease. RV-C15 was generated from the full-length cDNA clone and grown in HeLa-E8 cells expressing human CDHR3. BALB/c mice were inoculated intranasally with 5 x 106 ePFU RV-C15, RV-A1B or sham. Mice inoculated with RV-C15 showed lung viral titers of 1 x 105 TCID50 units 24 h after infection, with levels declining thereafter. IFN-α, β, γ and λ2 mRNAs peaked 24-72 hrs post-infection. Immunofluorescence verified colocalization of RV-C15, CDHR3 and acetyl-α-tubulin in mouse ciliated airway epithelial cells. Compared to RV-A1B, mice infected with RV-C15 demonstrated higher bronchoalveolar eosinophils, mRNA expression of IL-5, IL-13, IL-25, Muc5ac and Gob5/Clca, protein production of IL-5, IL-13, IL-25, IL-33 and TSLP, and expansion of type 2 innate lymphoid cells. Analogous results were found in mice treated with house dust mite before infection, including increased airway responsiveness. In contrast to Rorafl/fl littermates, RV-C-infected Rorafl/flIl7rcre mice deficient in ILC2s failed to show eosinophilic inflammation or mRNA expression of IL-13, Muc5ac and Muc5b. We conclude that, compared to RV-A1B, RV-C15 infection induces ILC2-dependent type 2 airway inflammation, providing insight into the mechanism of RV-C-induced asthma exacerbations.

Protective activity of asatone against ovalbumin-induced allergic asthma

Allergic asthma is a chronic lung disease characterized by wheezing, coughing, chest tightness and shortness of breath. Clinically, the treatments against asthma focus on controlling the symptoms rather than inhibiting recurrence radically. Additionally, local and systemic side effects caused by current treatments are worthy of attention. Therefore, a novel therapeutic strategy against asthma is needed. Asatone is a pharmacologically active component from Radix et Rhizoma Asari, which has anti-inflammatory effects in lipopolysaccharide-induced lung injury. In the present study, we showed that asatone could protect mice against OVA-induced asthma, as manifested by attenuating inflammation infiltration, mucus production, and airway hyperreactivity and suppressing the elevation of IL-4, IL-5, and IL-13 in broncho-alveolar lavage fluid. Overall, results of the present study support use of asatone as a potent therapeutic strategy for clinical treatment of allergic asthma.

Programmed T cell differentiation: Implications for transplantation

While T cells play a critical role in protective immunity against infection, they are also responsible for graft rejection in the setting of transplantation. T cell differentiation is regulated by both intrinsic transcriptional pathways as well as extrinsic factors such as antigen encounter and the cytokine milieu. Herein, we review recent discoveries in the transcriptional regulation of T cell differentiation and their impact on the field of transplantation. Recent studies uncovering context-dependent differentiation programs that differ in the setting of infection or transplantation will also be discussed. Understanding the key transcriptional pathways that underlie T cell responses in transplantation has important clinical implications, including development of novel therapeutic agents to mitigate graft rejection.

Decreased Risk of Influenza in Child and Adolescent Patients with Attention-Deficit Hyperactivity Disorder Following Methylphenidate Treatment: A Nationwide Cohort Study in Taiwan

BACKGROUND

Young individuals with attention-deficit hyperactivity disorder (ADHD) may have an elevated risk of influenza because of the difficulty in complying with the behavioral procedures that help protect against influenza. Moreover, the effects of sufficient methylphenidate treatment on influenza have received little attention.

OBJECTIVE

This study evaluated the association between ADHD medication usage and influenza and assessed the effect of duration of ADHD treatment on the risk of influenza using a nationwide population-based database.

METHODS

This study investigated methylphenidate usage and the risk of influenza among children and adolescents with ADHD. We identified 5259 young individuals aged less than 18 years who were diagnosed as having ADHD between 1996 and 2013 from the National Health Insurance Research Database of Taiwan, and we tested whether methylphenidate use affects influenza risk using Cox proportional hazard models.

RESULTS

After controlling for confounding factors, the results indicated that influenza risk significantly reduced in the group of ADHD patients who were prescribed methylphenidate for 90 days and more (hazard ratio [HR]: 0.62, 95% confidence interval [CI]: 0.52-0.75, p<0.001), demonstrating a 38% reduction in the risk of influenza in this group. However, this was not observed in the group of ADHD patients who used methylphenidate for 1-90 days (HR: 0.69, 95% CI: 0.89-1.05, p=0.12).

CONCLUSION

The lower incidence of influenza observed in the group prescribed with methylphenidate for a longer period highlights the importance of compliance to medication and psychoeducation with regard to ADHD management.

Rhinovirus species and tonsillar immune responses

Background

Rhinovirus A and C infections are important contributors to asthma induction and exacerbations. No data exist on the interaction of local immune responses in rhinovirus infection. Therefore, we aimed to determine the tonsillar immune responses according to rhinovirus A, B and C infections.

Methods

We collected tonsillar samples, nasopharyngeal aspirates and peripheral blood from 42 rhinovirus positive tonsillectomy patients. Fifteen respiratory viruses or their types were investigated from nasopharynx and tonsil tissue, and rhinovirus species were typed. The expression of 10 cytokines and 4 transcription factors (IFN-α, IFN-β, IFN-γ, IL-10, IL-13, IL-17, IL-28, IL-29, IL-37, TGF-β, FOXP3, GATA3, RORC2 and Tbet) were studied from tonsil tissue by quantitative PCR. A standard questionnaire of respiratory symptoms and health was filled by the patient or his/her guardian. The patients were divided into three groups by the determination of rhinovirus species.

Results

Overall, 16 patients had rhinovirus A, 12 rhinovirus B and 14 rhinovirus C infection. In rhinovirus B positive group there were significantly less men (P = 0.0072), less operated in spring (P = 0.0096) and more operated in fall (P = 0.030) than in rhinovirus A or C groups. Rhinovirus A positive patients had more respiratory symptoms (P = 0.0074) and particularly rhinitis (P = 0.036) on the operation day. There were no significant differences between the groups in virus codetection. In adjusted analysis, rhinovirus C infections were associated with increased IFN-α (P = 0.045) and decreased RORC2 expression (P = 0.025).

Conclusions

Rhinovirus species associated differently with clinical characteristics and tonsillar cytokine responses.

T-bet optimizes CD4 T-cell responses against influenza through CXCR3-dependent lung trafficking but not functional programming

Although clearance of many intracellular pathogens requires T-bet-dependent CD4 T cell programming, the extent to which T-bet is needed to direct protective CD4 responses against influenza is not known. Here, we characterize wild-type and T-bet-deficient CD4 cells during murine influenza infection. Surprisingly, although T-bet expression has broad impacts on cytokine production by virus-specific CD4 cells, the protective efficacy of T-bet-deficient effector cells is only marginally reduced. This reduction is due to lower CXCR3 expression, leading to suboptimal accumulation of activated T-bet-deficient cells in the infected lung. However, T-bet-deficient cells outcompete wild-type cells to form lung-resident and circulating memory populations following viral clearance, and primed T-bet-deficient mice efficiently clear supralethal heterosubtypic influenza challenges even when depleted of CD8 T cells. These results are relevant to the identification of more incisive correlates of protective T cells and for vaccines that aim to induce durable cellular immunity against influenza.

Loss of T-bet confers survival advantage to influenza-bacterial superinfection

The transcription factor, T-bet, regulates type 1 inflammatory responses against a range of infections. Here, we demonstrate a previously unaddressed role of T-bet, to influenza virus and bacterial superinfection. Interestingly, we found that T-bet deficiency did not adversely affect the efficacy of viral clearance or recovery compared to wild-type hosts. Instead, increased infiltration of neutrophils and production of Th17 cytokines (IL-17 and IL-22), in lungs of influenza virus-infected T-bet-/- mice, were correlated with survival advantage against subsequent infection by Streptococcus pneumoniae Neutralization of IL-17, but not IL-22, in T-bet-/- mice increased pulmonary bacterial load, concomitant with decreased neutrophil infiltration and reduced survival of T-bet-/- mice. IL-17 production by CD8+, CD4+ and γδ T cell types was identified to contribute to this protection against bacterial superinfection. We further showed that neutrophil depletion in T-bet-/- lungs increased pulmonary bacterial burden. These results thus indicate that despite the loss of T-bet, immune defences required for influenza viral clearance are fully functional, which in turn enhances protective type 17 immune responses against lethal bacterial superinfections.

In vivo experimental models of infection and disease

Human and animal models continue to play a crucial role in research to understand host immunity to rhinovirus (RV) and identify disease mechanisms. Human models have provided direct evidence that RV infection is capable of exacerbating chronic respiratory diseases and identified immunological processes that correlate with clinical disease outcomes. Mice are the most commonly used nonhuman experimental RV infection model. Although semipermissive, under defined experimental conditions sufficient replication occurs to induce host immune responses that recapitulate immunity and disease during human infection. The capacity to use genetically modified mouse strains and drug interventions has shown the mouse model to be an invaluable research tool defining causal relationships between host immunity and disease and supporting development of new treatments. Used in combination the insights achieved from human and animal experimental infection models provide complementary insights into RV biology and yield novel therapeutic options to reduce the burden of RV-induced disease.

Small Animal Models of Respiratory Viral Infection Related to Asthma

Respiratory viral infections are strongly associated with asthma exacerbations. Rhinovirus is most frequently-detected pathogen; followed by respiratory syncytial virus; metapneumovirus; parainfluenza virus; enterovirus and coronavirus. In addition; viral infection; in combination with genetics; allergen exposure; microbiome and other pathogens; may play a role in asthma development. In particular; asthma development has been linked to wheezing-associated respiratory viral infections in early life. To understand underlying mechanisms of viral-induced airways disease; investigators have studied respiratory viral infections in small animals. This report reviews animal models of human respiratory viral infection employing mice; rats; guinea pigs; hamsters and ferrets. Investigators have modeled asthma exacerbations by infecting mice with allergic airways disease. Asthma development has been modeled by administration of virus to immature animals. Small animal models of respiratory viral infection will identify cell and molecular targets for the treatment of asthma.

Attenuation of Influenza A Virus Disease Severity by Viral Coinfection in a Mouse Model

Influenza viruses and rhinoviruses are responsible for a large number of acute respiratory viral infections in human populations and are detected as copathogens within hosts. Clinical and epidemiological studies suggest that coinfection by rhinovirus and influenza virus may reduce disease severity and that they may also interfere with each other's spread within a host population. To determine how coinfection by these two unrelated respiratory viruses affects pathogenesis, we established a mouse model using a minor serogroup rhinovirus (rhinovirus strain 1B [RV1B]) and mouse-adapted influenza A virus (A/Puerto Rico/8/1934 [PR8]). Infection of mice with RV1B 2 days before PR8 reduced the severity of infection by a low or medium, but not high, dose of PR8. Disease attenuation was associated with an early inflammatory response in the lungs and enhanced clearance of PR8. However, coinfection by RV1B did not reduce PR8 viral loads early in infection or inhibit replication of PR8 within respiratory epithelia or in vitro Inflammation in coinfected mice remained focal compared to diffuse inflammation and damage in the lungs of mice infected by PR8. The timing of RV1B coinfection was a critical determinant of protection, suggesting that sufficient time is needed to induce this response. Finally, disease attenuation was not unique to RV1B: dose-dependent coinfection by a murine coronavirus (mouse hepatitis virus strain 1 [MHV-1]) also reduced the severity of PR8 infection. Unlike RV1B, coinfection with MHV-1 reduced early PR8 replication, which was associated with upregulation of beta interferon (IFN-β) expression. This model is critical for understanding the mechanisms responsible for influenza disease attenuation during coinfection by unrelated respiratory viruses.IMPORTANCE Viral infections in the respiratory tract can cause severe disease and are responsible for a majority of pediatric hospitalizations. Molecular diagnostics have revealed that approximately 20% of these patients are infected by more than one unrelated viral pathogen. To understand how viral coinfection affects disease severity, we inoculated mice with a mild viral pathogen (rhinovirus or murine coronavirus), followed 2 days later by a virulent viral pathogen (influenza A virus). This model demonstrated that rhinovirus can reduce the severity of influenza A virus, which corresponded with an early but controlled inflammatory response in the lungs and early clearance of influenza A virus. We further determined the dose and timing parameters that were important for effective disease attenuation and showed that influenza disease is also reduced by coinfection with a murine coronavirus. These findings demonstrate that coinfecting viruses can alter immune responses and pathogenesis in the respiratory tract.

Recent advances in understanding rhinovirus immunity

Rhinoviruses are the most common cause of upper respiratory tract infections. However, they can induce exacerbations of chronic obstructive pulmonary disease and asthma, bronchiolitis in infants, and significant lower respiratory tract infections in children, the immunosuppressed, and the elderly. The large number of rhinovirus strains (currently about 160) and their antigenic diversity are significant obstacles in vaccine development. The phenotype of immune responses induced during rhinovirus infection can affect disease severity. Recognition of rhinovirus and a balance of innate responses are important factors in rhinovirus-induced morbidity. Immune responses to rhinovirus infections in healthy individuals are typically of the T helper type 1 (Th1) phenotype. However, rhinovirus-driven asthma exacerbations are additionally characterised by an amplified Th2 immune response and airway neutrophilia. This commentary focuses on recent advances in understanding immunity toward rhinovirus infection and how innate and adaptive immune responses drive rhinovirus-induced asthma exacerbations.

Collateral Damage: What Effect Does Anti-CD4 and Anti-CD8α Antibody-Mediated Depletion Have on Leukocyte Populations?

Anti-CD4 or anti-CD8α Ab-mediated depletion strategies are widely used to determine the role of T cell subsets. However, surface expression of CD4 and CD8α is not limited to T cells and occurs on other leukocyte populations as well. Using both unbiased t-distributed stochastic neighbor embedding of flow cytometry data and conventional gating strategies, we assessed the impact of anti-CD4 and anti-CD8α Ab-mediated depletion on non-T cell populations in mice. Our results show that anti-CD4 and anti-CD8α Ab injections not only resulted in depletion of T cells but also led to depletion of specific dendritic cell subsets in a dose-dependent manner. Importantly, the extent of this effect varied between mock- and virus-infected mice. We also demonstrate the importance of using a second, noncompeting Ab (clone CT-CD8α) to detect CD8α⁺ cells following depletion with anti-CD8α Ab clone 2.43. Our study provides a necessary caution to carefully consider the effects on nontarget cells when using Ab injections for leukocyte depletion in all experimental conditions.

Tumor necrosis factor family member LIGHT acts with IL-1β and TGF-β to promote airway remodeling during rhinovirus infection

BACKGROUND

Rhinovirus (RV) can exacerbate allergen-driven asthma. However, it has been suggested that serial infections with RV may also lead to asthma-like features in childhood without prior allergen exposure.

AIM

We sought to test the effects of RV infection in the absence of allergen challenge on lung tissue remodeling and to understand whether RV induced factors in common with allergen that promote remodeling.

METHODS

We infected C57BL/6 mice multiple times with RV in the absence or presence of allergen to assess airway remodeling. We used knockout mice and blocking reagents to determine the participation of LIGHT (TNFSF14), as well as IL-1β and TGF-β, each previously shown to contribute to lung remodeling driven by allergen.

RESULTS

Recurrent RV infection without allergen challenge induced an increase in peribronchial smooth muscle mass and subepithelial fibrosis. Rhinovirus (RV) induced LIGHT expression in mouse lungs after infection, and alveolar epithelial cells and neutrophils were found to be potential sources of LIGHT. Accordingly, LIGHT-deficient mice, or mice where LIGHT was neutralized, displayed reduced smooth muscle mass and lung fibrosis. Recurrent RV infection also exacerbated the airway remodeling response to house dust mite allergen, and this was significantly reduced in LIGHT-deficient mice. Furthermore, neutralizing IL-1β or TGF-β also limited subepithelial fibrosis and/or smooth muscle thickness induced by RV.

CONCLUSION

Rhinovirus can promote airway remodeling in the absence of allergen through upregulating common factors that also contribute to allergen-associated airway remodeling.

Effects of 1,25-dihydroxyvitamin D3 in an ovalbumin-induced allergic rhinitis model

IL-17-producing Th17 cells play an important role in allergic airway diseases, but their local expression and regulation in allergic rhinitis (AR) is not well understood. This study investigated the effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)₂D₃) on T-bet expression, Th1 cells, Th2 cells, Th17 cells and IL-33-positive epithelial cells in AR. C57BL/6 mice were intranasally sensitized and challenged with ovalbumin (OVA), and 1,25-(OH)₂D₃ was intraperitoneally injected into AR mice. Cytokine levels were measured with enzyme-linked immunosorbent assays, phenotypic analysis of Th1, Th2 and Th17 cells in the spleen was completed with flow cytometry, and the CD4⁺IL-17⁺ cells in the Nasopharynx-associated lymphoid tissue (NALT) and IL-33-positive cells in nasal mucosa was evaluated with immunofluorescence microscopy. AR mice shown significantly increased Th2 and Th17 cell ratio in spleen, IL-17 level in serum, IL-5 and IL-13 levels in NALF but a lower number of IL-33-positive epithelial cells and Th1 response (Th1 and Tbet⁺Th1 cell ratio in the spleen and serum IFN-γ level) than the control mice.1,25-(OH)₂D₃ treatment significantly decreased the number of sneezing, nasal rubbing, OVA-sIgE and IL-17 in serum, IL-5 and IL-13 levels in NALF, Th17 cell ratio in the spleen and the histological of nasal mucosal but increased the number of IL-33-positive epithelial cells in AR mice. However, 1,25-(OH)₂D₃ treatment did not significantly influence IFN-γ level in serum, and Th1, Tbet⁺Th1 and Th2 cell ratio in spleen. Thus, 1,25-(OH)₂D₃ may exert anti-allergic effects by suppressing Th17 responses and local production of IL-5 and IL-13 cytokines.