Inflammatory profiles in nasal mucosa of patients with persistent vs intermittent allergic rhinitis

Deciphering the Interplay between the Epithelial Barrier, Immune Cells, and Metabolic Mediators in Allergic Disease

Chronic exposure to harmful pollutants, chemicals, and pathogens from the environment can lead to pathological changes in the epithelial barrier, which increase the risk of developing an allergy. During allergic inflammation, epithelial cells send proinflammatory signals to group 2 innate lymphoid cell (ILC2s) and eosinophils, which require energy and resources to mediate their activation, cytokine/chemokine secretion, and mobilization of other cells. This review aims to provide an overview of the metabolic regulation in allergic asthma, atopic dermatitis (AD), and allergic rhinitis (AR), highlighting its underlying mechanisms and phenotypes, and the potential metabolic regulatory roles of eosinophils and ILC2s. Eosinophils and ILC2s regulate allergic inflammation through lipid mediators, particularly cysteinyl leukotrienes (CysLTs) and prostaglandins (PGs). Arachidonic acid (AA)-derived metabolites and Sphinosine-1-phosphate (S1P) are significant metabolic markers that indicate immune dysfunction and epithelial barrier dysfunction in allergy. Notably, eosinophils are promoters of allergic symptoms and exhibit greater metabolic plasticity compared to ILC2s, directly involved in promoting allergic symptoms. Our findings suggest that metabolomic analysis provides insights into the complex interactions between immune cells, epithelial cells, and environmental factors. Potential therapeutic targets have been highlighted to further understand the metabolic regulation of eosinophils and ILC2s in allergy. Future research in metabolomics can facilitate the development of novel diagnostics and therapeutics for future application.

R, C.R.K. B, N. R. A Study on the Significance of Nasal Smear Eosinophil Count and Blood Absolute Eosinophil Count in Patients with Allergic Rhinitis of Varied Severity of Symptoms

Introduction: Rhinitis is defined as inflammation of nasal mucosa. Allergic rhinitis is the most common type of chronic rhinitis with increasing prevalence. Tests such as nasal smear for eosinophilia, Skin prick test, Serum absolute eosinophil count and Immunoglobulin IgE helps us in diagnosis of allergic rhinitis. Objective: To evaluate the efficacy of the nasal smear for eosinophilia and blood absolute eosinophil count tests to diagnose allergic rhinitis in patients with varied severity of symptoms. Materials and methods: In this prospective study, all patients above 12 years of age with symptoms suggestive of allergic rhinitis were enrolled in our study. Severity assessment was done by visual analog scoring and Total nasal outcome scoring. Diagnostic nasal endoscopy with nasal smear for eosinophilia, complete blood count and blood absolute eosinophil count tests were done. Results: A total of 60 patients were enrolled in the present study. Age ranged from 13 to 55 years with female preponderance. The most common symptom was rhinorrhea found in 100% of study population, followed by sneezing present in 57 (93.5%) patients. 10 out of 12 patients with mild intermittent symptoms had < 5% of eosinophil elicited in nasal smear and 2 patients had negative smear of eosinophils. Only 13% had mild eosinophilia. In this study, in those patients with mild intermittent symptoms neither nasal smear eosinophilia nor Blood absolute eosinophil count was found to be significant. Conclusions: Nasal smear cytology and blood absolute eosinophil count were found to be significant only in patients with moderate-severe symptoms. Those patients with mild intermittent symptoms need not be tested as it will be insignificant. In these patients, we must rely on the visual analogue score based on the severity of symptoms rather than laboratory tests.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03945-5.

T cell transcriptional factors in allergic rhinitis and its association with clinical features

BACKGROUND

Th2 cells are crucially important in allergic disease and the possible involvement of Treg and Th17 cells has not been clearly identified.

OBJECTIVE

To identify the mRNA expression of T cell transcription factors in nasal mucosa in patients with allergic rhinitis (AR) and to reveal their correlations with clinical features.

METHODS

Eighteen patients with AR and 12 controls with turbinate hypertrophy were included. mRNA expression of the following transcriptional factors in nasal mucosa were measured by quantitative polymerase chain reaction; T-bet (Th1), GATA3 (Th2), retinoic acid-related orphan receptor C (RORC; Th17), and forkhead box P3 (Foxp3; Treg). mRNA expression was compared among groups and correlation between mRNA expression level and clinical features (rhinitis symptoms, eosinophil count, and IgE) were also investigated.

RESULTS

GATA3 and RORC were significantly increased and Foxp3 was significantly decreased in the AR group. Moderate-to-severe AR group also had increased expression of GATA3 and RORC than mild AR group, suggesting severity of AR influence expression of transcription factors. Correlation analysis showed that none of these transcription factors were associated with severity of clinical symptoms, eosinophil counts and skin prick test severity and that IgE level was significantly correlated with expression level of GATA3 and RORC, suggesting an association of IgE production with Th2 and Th17 cells.

CONCLUSION

Increased mRNA expression of GATA3 (Th2), increased expression of RORC and decreased expression of Foxp3 may be important in pathogenesis of AR. GATA3 and RORC may be closed related with IgE level.

Solitary chemosensory cells and bitter taste receptor signaling in human sinonasal mucosa

BACKGROUND

Solitary chemosensory cells (SCCs) are specialized cells in the respiratory epithelium that respond to noxious chemicals including bacterial signaling molecules. SCCs express components of bitter taste transduction including the taste receptor type 2 (TAS2R) bitter taste receptors and downstream signaling effectors: α-Gustducin, phospholipase Cβ2 (PLCβ2), and transient receptor potential cation channel subfamily M member 5 (TRPM5). When activated, SCCs evoke neurogenic reflexes, resulting in local inflammation. The purpose of this study was to test for the presence SCCs in human sinonasal epithelium, and to test for a correlation with inflammatory disease processes such as allergic rhinitis and chronic rhinosinusitis.

METHODS

Patient demographics and biopsies of human sinonasal mucosa were obtained from control patients (n = 7) and those with allergic rhinitis and/or chronic rhinosinusitis (n = 15). Reverse transcription polymerase chain reaction (RT-PCR), quantitative PCR (qPCR), and immunohistochemistry were used to determine whether expression of signaling effectors was altered in diseased patients.

RESULTS

RT-PCR demonstrated that bitter taste receptors TAS2R4, TAS2R14, and TAS2R46, and downstream signaling effectors α-Gustducin, PLCβ2, and TRPM5 are expressed in the inferior turbinate, middle turbinate, septum, and uncinate of both control and diseased patients. PLCβ2/TRPM5-immunoreactive SCCs were identified in the sinonasal mucosa of both control and diseased patients. qPCR showed similar expression of α-Gustducin and TRPM5 in the uncinate process of control and diseased groups, and there was no correlation between level of expression and 22-item Sino-Nasal Outcomes Test (SNOT-22) or pain scores.

CONCLUSION

SCCs are present in human sinonasal mucosa in functionally relevant areas. Expression level of signaling effectors was similar in control and diseased patients and did not correlate with measures of pain and inflammation. Further study into these pathways may provide insight into nasal inflammatory diseases and may offer potential therapeutic targets.