Limosilactobacillus reuteri DSM-17938 for preventing cough in adults with mild allergic asthma: A double-blind randomized placebo-controlled cross-over study.

BACKGROUND: Cough is a common troublesome symptom in asthma which is neuronally mediated. Limosilactobacillus reuteri DSM-17938 (L. reuteri DSM-17938) is a probiotic shown to be effective in pre-clinical models at suppressing neuronal responses to capsaicin, a transient receptor potential vanilloid agonist (TRPV1). OBJECTIVE: Investigate the effects of DSM-17938 versus matched placebo on capsaicin-evoked coughs in mild allergic asthmatics. METHODS: We performed a 4-visit, randomized, double-blind, placebo-controlled, two-way cross-over study comparing full dose cough responses with inhaled capsaicin in mild allergic asthmatics after 1 month of treatment with DSM-17938 compared with matched placebo. Randomization and allocation to trial group were carried out by a central computer system. Histamine skin prick testing, airway hyper-responsiveness and inflammatory cells in induced sputum were measured at every visit. Blood was collected to extract PBMCs and stimulated with CD3/CD28 to ascertain the effects of DSM-17938 /placebo on T-cell cytokine responses. RESULTS: Seventeen subjects were recruited and 15 completed the study (8 females, mean age 27.3 years). There was no difference in the change in maximum capsaicin-evoked coughs (Emax) after treatment with L. reuteri DSM-17938 compared with placebo [mean difference 2.07 coughs (95% CI -2.77 to 6.91, p = .38) or relative changes in geometric mean ratios for the dose evoking at least half the Emax (ED50) [1.05 (95% CI 0.31-3.58, p = .94)], concentration evoking 2 coughs (C2) [0.63 (0.26-1.53), p = .28] and 5 coughs (C5) [0.79 (0.25-2.50), p = .67]. There was no effect on histamine skin prick wheal size, intensity of itch sensation, methacholine PC20, airway inflammation or T-cell responses after stimulation with CD3/CD28. There were no serious adverse events. One subject developed a mild upper respiratory tract infection and another mild transient nausea whilst on DSM-17938. CONCLUSION: In this small study in adults with mild allergic asthma, we found no evidence that L. reuteri DSM-17938 has any systemic effects on airway nerves, smooth muscle, sputum inflammatory cells, skin responses or T-cell responses after oral consumption. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT03603522.

Effect of benralizumab on inflammation in skin after intradermal allergen challenge in patients with moderate-to-severe atopic dermatitis.

Background: Atopic dermatitis (AD) is a skin barrier dysfunction characterized by tissue eosinophilia. Objective: In patients with AD, we evaluated the effect of eosinophil depletion with benralizumab on markers of inflammation in skin after intradermal allergen challenge. Methods: A total of 20 patients with moderate-to-severe AD completed a randomized, double-blind, placebo-controlled parallel-group study comparing 3 doses of benralizumab (30 mg each) administered subcutaneously every 4 weeks (n = 9) with placebo (n = 11). Allergen and saline control intradermal challenges were conducted before and after treatment, with skin biopsy samples collected 24 hours after challenge. Early and late cutaneous responses were measured by skin wheal size. Levels of eosinophils and IL-5 receptor-α-bearing cells, including eosinophil progenitor (EoP) cells, basophils, and mast cells, in papillary dermis were measured by immunofluorescence microscopy, and levels of EoP cells, hematopoietic progenitor cells, and type 2 innate lymphoid cells in the blood were measured by flow cytometry. Outcomes were compared between the placebo and benralizumab treatment groups by using the Mann-Whitney U test. Results: Benralizumab reduced eosinophil counts in the blood (P < .0001) and allergen-challenged skin, as measured by hematoxylin and eosin staining and eosinophil cationic protein antibody concentration (P < .05). Benralizumab lowered the levels of EoP cells, mast cells, and basophils in the skin, as well as the levels of EoP cells, hematopoietic progenitor cells, and type 2 innate lymphoid cells in the blood (all P < .05). There was a trend toward improvement in the early cutaneous response (P = .095) but no effect on the late cutaneous response. Conclusion: In patients with moderate-to-severe AD, benralizumab treatment significantly inhibited accumulation of eosinophils and other IL-5 receptor-α-expressing cells in the papillary dermis after intradermal allergen challenge. Targeting IL-5 receptor-α-positive cells did not modulate the size of the allergen-induced skin wheal (ClincialTrials.gov identifier NCT03563066).