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Background: Group 2 innate lymphoid cells (ILC2s) have been found to take part in type 2 inflammation by secreting TH2 cytokines. Apolipoprotein A-I (Apo-AI), a major structural and functional protein of high-density lipoproteins, has anti-inflammatory effects on neutrophils, monocytes, macrophages, and eosinophils. However, its effects on ILC2s are not well characterized. Objective: We aimed to investigate the effect of Apo-AI on the proliferation and function of ILC2s as well as its possible mechanism. Methods: The protein expression of Apo-AI and the percentage of ILC2s in peripheral blood between 20 allergic rhinitis patients and 20 controls were detected by ELISA and flow cytometry. The effect of Apo-AI and miR-155 on ILC2 proliferation and function was detected by tritiated thymidine incorporation and ELISA. Anima models were adopted to verify the effect of Apo-AI in vivo. Results: Elevated expression of Apo-AI was observed in allergic rhinitis patients. Apo-AI promotes ABCA1 expression by ILC2s, which can be inhibited by anti–Apo-AI. Apo-AI decreased ILC2 proliferation and the microRNA levels of GATA3 and RORα from ILC2s. The miR-155 overexpression promoted the upregulation of GATA3 and type II cytokines from ILC2s, while the addition of Apo-AI or miR-155 inhibitor significantly inhibited expression of GATA3 and type II cytokines by ILC2s. Apo-AI−/− mice showed as enhanced allergen-induced airway inflammation. The miR-155 inhibitor can reverse the enhanced allergen-induced airway inflammation in Apo-AI−/− mice, while miR-155 mimics can reverse the decreased allergen-induced airway inflammation in Apo-AI–treated mice. Conclusion: Apo-AI suppressed the proliferation and function of ILC2s through miR-155 in allergic rhinitis. Our data provide new insights into the mechanism of allergen-induced airway inflammation.

Background: Allergen-specific immunotherapy, including subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), improves the disease progression of allergic rhinitis (AR). SCIT and SLIT exhibit similar efficacy, but SLIT has less systemic reactions. However, few studies have investigated the underlying mechanisms of SLIT treatment. In this study, we explored the efficacy of SLIT under different treatment durations and immunological changes. Methods: This retrospective study was conducted from August 2017 to August 2022 in our hospital. A total of 314 children who underwent SLIT were divided into the following groups based on their treatment duration: the 1 year group (6 months–1 year), the 2 years group (1–2 years), and the 3 years group (2–3 years). The treatment efficacy was confirmed using a combined symptom and medication score (SMS). Multiple serum cytokines were measured using Luminex. Various immune cells in PBMCs were determined using flow cytometry. Results: The total nasal symptom score (TNSS), rescue medication score (RMS), and SMS of the 3 years group was significantly different from those of the 1 years and 2 years groups. At the end of the 2 years following cessation of SLIT, the following results were observed in the 3 years group: 1) the TNSS, RMS, and SMS had significantly improved, 2) the serum IL-10, TGF-beta, and IL-35 levels had increased significantly, and 3) the percentages of regulatory T cell, regulatory B cell, and follicular regulatory T cell increased significantly. Conclusion: Our results suggest that 3 years of SLIT is necessary for long-term effects and continued immunological changes.

Background: Osteopontin (OPN) can regulate Th2 inflammation in allergic rhinitis (AR). A recent study suggested that group II innate lymphoid cells (ILC2s) were very important for airway inflammation. But the role of OPN in ILC2s regulation is not explored. Methods: Purified ILC2s were stimulated by human recombinant OPN. The expression of GATA3 and RORα was assayed using real-time polymerase chain reaction (PCR) and enzyme linked immunosorbent assay. MiR-181a was transfected into eosinophils to test the OPN production. The protein concentrations of interleukin (IL)-5 and IL-13 were examined using ELISA. Purified eosinophils and ILC2s were cocultured and stimulated by OPN and the activation of eosinophils was detected by ELISA. Results: After OPN stimulation, the ILC2s proliferation, the mRNA levels of GATA3 and RORα, the protein of GATA3, RORα, IL-5 and IL-13 expression were up-regulated significantly in a dose dependent manner. Eosinophils cultured alone transfected with miR-181a mimics produced less OPN protein compared with eosinophils transfected with miR-control, whereas OPN production was significantly promoted when miR-181a inhibitor was transfected. In the eosinophils and ILC2s coculture system, eosinophil cationic protein (ECP) production induced by OPN or IL-33 were significantly higher than ECP production in eosinophils culture system. OPN presented similar potency with IL-33 in the activation of eosinophils. When anti-IL-5 antibody was added, the production of ECP was significantly inhibited. Conclusions: Our data for the first time provided new evidence that OPN played important roles in innate immunity of AR by regulation of ILC2s and the interaction between ILC2s and eosinophils.

Background: Allergic rhinitis (AR) is a frequent inflammatory disorder of the upper respiratory tract, which has complex patterns of inheritance. Accumulating evidence has shown the key roles of DNA damage in inflammatory diseases, and the base excision repair (BER) is the primary pathway responsible for DNA repair during inflammation. Methods: Here, we performed a case-control study to investigate the associations between 20 potentially functional single nucleotide polymorphisms (SNPs) in 6 BER pathway genes (PARP1, hOGG1, FEN1, APEX1, LIG3, and XRCC1) and AR susceptibility in 508 AR cases and 526 controls which originated in China. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for evaluating the association strength. Results: We found that hOGG1 rs1052133 G > C and XRCC1 rs2682585 G > A polymorphisms were associated with decreased AR risk (adjusted OR = 0.67, 95% CI = 0.47–0.94, P = 0.022; and adjusted OR = 0.21, 95% CI = 0.06–0.79, P = 0.022, respectively). Stratification analysis suggested that: hOGG1 rs1052133 GC/CC genotype reduced AR risk in subjects among following subgroups: age ≤60 months, females, and moderate AR; XRCC1 rs2682585 GG genotype decreased AR risk in subjects age >60 months, and LIG3 rs1052536 TT genotype increased AR risk in subjects of severe AR. Conclusion: Our findings indicated that the genetic variants of hOGG1, XRCC1, and LIG3 genes might affect AR susceptibility in the Chinese population, which will provide novel insight into the genetic underpinnings of AR from the DNA damage level.

Background: The histopathology of pediatric chronic rhinosinusitis with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP) is rarely reported due to low prevalence or the unavailability of tissue samples. Hence, we aimed to characterize and compare the histologic features and protein expression of Th1/Th2/Th17-related cytokines in pediatric CRSsNP and CRSwNP. Methods: The histologic characteristics of 15 children with CRSsNP, 52 children with CRSwNP, and 12 control participants were analyzed using hematoxylin and eosin staining. The expression of Th1/Th2/Th17-related cytokines were examined using immunohistochemistry and the enzyme-linked immunosorbent assay. Results: Pediatric subjects with CRSwNP had more intact epithelium and less submucosal mucous glands compared to those with CRSsNP. Tissue eosinophils were more prevalent in the younger CRSwNP group compared to the older CRSwNP or the CRSsNP groups. The protein concentrations of Th2 cytokines were significantly higher in the CRSwNP group than the CRSsNP group or the control group. Moreover, the protein concentrations of Th17 cytokines were significantly higher in the younger CRSwNP group than the older CRSwNP group or the CRSsNP and control groups. The protein concentrations of Th1 and Th17 cytokines were also significantly higher in the CRSsNP group than the control group. Compared with non-eosinophilic CRSwNP, eosinophilic CRSwNP presented with elevated protein concentrations of Th1 and Th17 cytokines. Conclusion: For the first time, we showed that pediatric CRSwNP presents as eosinophilic with Th2/Th17 inflammation, whereas CRSsNP presents as Th1/Th17 inflammation. Our study may provide a theoretical basis for the precise treatment of pediatric CRS in the future.