LEAP-2, LL-37 and RNase7 in tonsillar tissue: downregulated expression in seasonal allergic rhinitis.

In the upper airway, the production of antimicrobial peptides (AMPs) protects against bacteria, viruses and fungi. Previous investigations have revealed downregulated expression of AMPs in different manifestations of allergic disease. In this study, we examined the expression of LL-37, Ribonuclease7 (RNase7) and Liver-expressed antimicrobial peptide 2 (LEAP-2) in tonsillar tissue and studied a possible relation to seasonal allergic rhinitis (SAR). Tonsils, obtained from patients with SAR and nonallergic controls, were examined for the occurrence of LL-37, RNase7 and LEAP-2 with real-time RT-PCR and immunohistochemistry. Tonsillar mononuclear cells were cultured in presence or absence of LEAP-2 or LL-37 and analyzed for cytokine levels using ELISA. mRNA and protein for LL-37, RNase 7 and LEAP-2 were found in all tonsils. Immunohistochemistry revealed prominent staining for LL-37 and RNase7 in the tonsillar epithelium, whereas a moderate staining was seen with LEAP-2. Real-time RT-PCR showed a downregulation of RNase7 and LEAP-2 in the allergic as compared to the nonallergic group. Mononuclear cells cultured in presence of LEAP-2 or LL-37 demonstrated reduced levels of IL-10. The present study demonstrates the presence and function of LEAP-2, LL-37 and RNase7 in tonsils. Moreover, a downregulation of LEAP-2 and RNase7 is seen in SAR patients, indicating that allergic individuals may be more susceptible to respiratory tract infections due to an impaired antimicrobial defense.

Upregulated levels of human ß-defensins in patients with seasonal allergic rhinitis after allergen-specific immunotherapy treatment.

BACKGROUND: Antimicrobial peptides (AMPs) are important actors in the innate immune system. One class of AMPs is the human ß-defensins (HBDs), a group of small peptides with a broad spectrum of antimicrobial activities. Expression of HBDs is downregulated in different manifestations of allergic disease. In this study, we examine whether allergen-specific immunotherapy (ASIT) affects the nasal levels of HBDs in patients with seasonal allergic rhinitis (SAR). METHODS: Nasal biopsies were examined for the occurrence of HBD1-3 with real-time reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. Nasal lavage (NAL) fluids from healthy individuals, untreated SAR patients and SAR patients before and after ASIT were analyzed for levels of HBD1-3 using enzyme-linked immunosorbent assay (ELISA). RESULTS: Examination of nasal biopsies revealed HBD1-3 expression at gene level as well as at protein level in all samples tested. HBD1 and HBD3 messenger RNA (mRNA) levels were downregulated in SAR patients compared to healthy individuals. All HBDs were found in NAL fluids. SAR patients having completed 3 years of ASIT displayed higher levels of HBD1 and HBD2 than before treatment, whereas levels of HBD3 were unaffected. CONCLUSION: The present study demonstrates an upregulation of HBD1 and HBD2 in SAR patients after completion of ASIT. This may reflect the importance of an intact innate immune response as part of our defense against infections among allergic individuals.

Reduced tonsillar expression of human ß-defensin 1, 2 and 3 in allergic rhinitis.

Airway infections are known to cause exacerbations of allergy and asthma. Tonsils constitute a primary site for microbial recognition and triggering of the immune system in the airways. Human ß-defensins (HBDs) are antimicrobial peptides with an important role in this defense. Our aim was to investigate HBD1-3 in tonsillar tissue and their potential role in allergic rhinitis (AR). Tonsils, obtained from patients with AR and non-allergic controls, and isolated tonsillar CD4(+), CD8(+) and CD19(+) lymphocytes were analyzed for HBD1-3 expression using real-time RT-PCR and/or immunohistochemistry. Tonsillar tissue, mixed tonsillar lymphocytes and airway epithelial cells (AECs) were cultured with or without IL-4, IL-5, IL-13 or histamine followed by measurements of HBD1-3 release using ELISA. HBD1-3 were present in tonsillar tissue, including epithelial, CD4(+), CD8(+) and CD19(+) cells. The expression was reduced in allergic compared to healthy tonsils. Stimulation of AECs with IL-4, IL-5 and histamine down-regulated the HBD release, whereas no effects were seen in cultured tonsils or lymphocytes. This study demonstrates presence of HBD1-3 in tonsils and that the levels are reduced in patients with AR. Together with the down-regulation of HBDs in epithelial cells in the presence of allergic mediators suggest that AR patients have an impaired antimicrobial defense that might make them more susceptible to respiratory tract infections.

Retinoic acid-inducible gene 1-like receptors in the upper respiratory tract.

BACKGROUND: Retinoic acid-inducible gene 1-like receptors (RLRs) are a novel family of pattern recognition receptors that include retinoic acid-inducible gene 1 (RIG-1), melanoma differentiation-associated gene 5 (MDA-5), and laboratory of genomics and physiology 2 (LGP-2). The knowledge of RLRs and their function in the human airway is limited. This study explores the role of RLRs in the upper respiratory tract. METHODS: Tonsils, adenoids, nasal polyps, and biopsy specimens from the nasal mucosa were examined for the occurrence of the RIG-1, MDA-5, and LGP-2 using real-time reverse-transcription polymerase chain reaction and immunohistochemistry. The nasopharyngeal epithelial cell line FaDu was cultured with the RIG-1/MDA-5 ligand poly(I:C)/LyoVec (Invivogen, San Diego, CA) and analyzed for cytokine release using ELISA. RESULTS: RIG-1, MDA-5, and LGP-2 mRNA were found in all tissues tested. The airway epithelium appeared to be their most prominent location. The RIG-1 and MDA-5 mRNA levels were higher in nasal polyps than in normal nasal mucosa, a state that seemed to be reversed by local steroid treatment. Culture of FaDu with poly(I:C)/LyoVec resulted in IL-6 and IL-8 release. No alteration in RLR expression in tonsils was seen on infection. CONCLUSION: This study shows the presence and functional activity of RLRs in the human upper airways. It also suggests a role for RLRs in nasal polyposis.

Topical steroids do not downregulate expression of growth-related oncogene-alpha in nasal polyps.

CONCLUSIONS: Topical steroids did not affect expression of growth-related oncogene-alpha (GRO-alpha) in nasal polyps. The results of this study suggest roles for steroid-resistant gene expression in the pathogenesis of nasal polyps and point to the need for additional pharmacological strategies. OBJECTIVE: Infiltration of inflammatory cells is believed to play a role in the development of nasal polyps. GRO-alpha is a chemokine that recruits and activates neutrophils and also possesses growth stimulatory and angiogenetic properties. An increased presence of GRO-alpha has been demonstrated in nasal polyps compared with normal nasal tissue. In this study we evaluate the presence and expression levels of GRO-alpha in nasal polyps before and after glucocorticoid treatment. MATERIAL AND METHODS: Nasal polyps were surgically removed in patients before and 6 weeks after treatment with topically applied fluticasone. GRO-alpha gene expression and the presence of GRO-alpha peptide were detected in polyp tissue by means of in situ hybridization, quantitative real-time reverse transcriptase polymerase chain reaction and immunohistochemistry. RESULTS: Strong GRO-alpha gene expression and the presence of GRO-alpha peptide were seen in both the epithelium and stromal inflammatory cells of nasal polyps. No differences in gene expression levels in tissue homogenates were found when untreated polyp tissue was compared with polyps treated for 6 weeks with topically applied steroids.