Airway hyperresponsiveness correlates with airway TSLP in asthma independent of eosinophilic inflammation.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is released from the airway epithelium in response to various environmental triggers, inducing a type-2 inflammatory response, and is associated with airway inflammation, airway hyperresponsiveness (AHR), and exacerbations. TSLP may also induce AHR via a direct effect on airway smooth muscle and mast cells, independently of type-2 inflammation, although association between airway TSLP and AHR across asthma phenotypes has been described sparsely. OBJECTIVES: This study sought to investigate the association between AHR and levels of TSLP in serum, sputum, and bronchoalveolar lavage in patients with asthma with and without type-2 inflammation. METHODS: A novel ultrasensitive assay was used to measure levels of TSLP in patients with asthma (serum, n = 182; sputum, n = 81; bronchoalveolar lavage, n = 85) and healthy controls (serum, n = 47). The distribution and association among airway and systemic TSLP, measures of AHR, type-2 inflammation, and severity of disease were assessed. RESULTS: TSLP in sputum was associated with AHR independently of levels of eosinophils and fractional exhaled nitric oxide (ρ = 0.49, P = .005). Serum TSLP was higher in both eosinophil-high and eosinophil-low asthma compared to healthy controls: geometric mean: 1600 fg/mL (95% CI: 1468-1744 fg/mL) and 1294 fg/mL (95% CI: 1167-1435 fg/mL) versus 846 fg/mL (95% CI: 661-1082 fg/mL), but did not correlate with the level of AHR. Increasing age, male sex, and eosinophils in blood were associated with higher levels of TSLP in serum, whereas lung function, inhaled corticosteroid dose, and symptom score were not. CONCLUSIONS: The association between TSLP in sputum and AHR to mannitol irrespective of markers of type-2 inflammation further supports a role of TSLP in AHR that is partially independent of eosinophilic inflammation.

Allergen Immunotherapy Enhances Airway Epithelial Antiviral Immunity in Patients with Allergic Asthma (VITAL Study): A Double-Blind Randomized Controlled Trial.

Rationale: Allergic asthma is linked to impaired bronchial epithelial secretion of IFNs, which may be causally linked to the increased risk of viral exacerbations. We have previously shown that allergen immunotherapy (AIT) effectively reduces asthma exacerbations and prevents respiratory infections requiring antibiotics; however, whether AIT alters antiviral immunity is still unknown. Objectives: To investigate the effect of house dust mite sublingual AIT (HDM-SLIT) on bronchial epithelial antiviral and inflammatory responses in patients with allergic asthma. Methods: In this double-blind, randomized controlled trial (VITAL [The Effect of Allergen Immunotherapy on Anti-viral Immunity in Patients with Allergic Asthma]), adult patients with HDM allergic asthma received HDM-SLIT 12-SQ or placebo for 24 weeks. Bronchoscopy was performed at baseline and at Week 24, which included sampling for human bronchial epithelial cells. Human bronchial epithelial cells were cultured at baseline and at Week 24 and stimulated with the viral mimic polyinosinic:polycytidylic acid (poly(I:C)). mRNA expression was quantified using qRT-PCR, and protein concentrations were measured using multiplex ELISA. Measurements and Main Results: Thirty-nine patients were randomized to HDM-SLIT (n = 20) or placebo (n = 19). HDM-SLIT resulted in increased polyinosinic:polycytidylic acid-induced expression of IFN-ß at both the gene (P = 0.009) and protein (P = 0.02) levels. IFN-λ gene expression was also increased (P = 0.03), whereas IL-33 tended to be decreased (P = 0.09). On the other hand, proinflammatory cytokines IL-6 (P = 0.009) and TNF-α (tumor necrosis factor-α) (P = 0.08) increased compared with baseline in the HDM-SLIT group. There were no significant changes in TSLP (thymic stromal lymphopoietin), IL-4, IL-13, and IL-10. Conclusions: HDM-SLIT improves bronchial epithelial antiviral resistance to viral infection. These results potentially explain the efficacy of HDM-SLIT in reducing exacerbations in allergic asthma. Clinical trial registered with www.clinicaltrials.gov (NCT04100902).

An in-well direct lysis method for rapid detection of SARS-CoV-2 by real time RT-PCR in eSwab specimens.

BACKGROUND: Diagnostic real time reverse transcription PCR (rRT-PCR) is usually done using nucleic acid (NA) purified from the sample. In the SARS-CoV-2 pandemic reagents and utensils for NA purification has been in short supply. This has generated interest in methods that eliminate the need for NA purification. OBJECTIVES: To investigate if addition of detergent to rRT-PCR master mix (MM) enabled in-well direct lysis and detection of SARS-CoV-2 in clinical eSwab specimens. STUDY DESIGN: IGEPAL-CA-630 (IGEPAL) was added to SARS-CoV-2 MM to 0.3 % final concentration and crude sample was added directly to the PCR well containing MM. Cycle of positivity (Cp) and categorical agreement was compared in samples tested in standard rRT-PCR after NA purification and in in-well lysis, direct rRT-PCR. RESULTS: In-well lysis direct rRT-PCR detected SARS-CoV-2 in 27/30 previously SARS-CoV-2+ samples with an average bias of 3.26 cycles (95 %CI: 0.08-6.43 cycles). All 30 previously test negative samples remained negative when tested in in-well lysis, direct PCR. CONCLUSIONS: Supplementation of detergent to MM was shown to be useful for the detection of SARS CoV-2 in eSwab specimens (COPAN) by direct rRT-PCR without prior NA purification.