Sharif H, Singh I, Kouser L, Mösges R, Bonny MA, Karamani A, Parkin RV, Bovy N, Kishore U, Robb A, Katotomichelakis M, Holtappels G, Derycke L, Corazza F, von Frenckell R, Wathelet N, Duchateau J, Legon T, Pirotton S, Durham SR, Bachert C, and Shamji MH
Background: A 3-week short-course of adjuvant-free hydrolysates of Lolium perenne peptide (LPP) immunotherapy for rhinoconjunctivitis with or without asthma over 4 physician visits is safe, well tolerated, and effective., Objective: We sought to investigate immunologic mechanisms of LPP immunotherapy in a subset of patients who participated in a phase III, multicenter, randomized, double-blind, placebo-controlled trial (clinical.govNCT02560948)., Methods: Participants were randomized to receive LPP (n = 21) or placebo (n = 11) for 3 weeks over 4 visits. Grass pollen-induced basophil, T-cell, and B-cell responses were evaluated before treatment (visit [V] 2), at the end of treatment (V6), and after the pollen season (V8)., Results: Combined symptom and rescue medication scores (CSMS) were lower during the peak pollen season (-35.1%, P = .03) and throughout the pollen season (-53.7%, P = .03) in the LPP-treated group compared with those in the placebo-treated group. Proportions of CD63 + and CD203c bright CRTH2 + basophils were decreased following LPP treatment at V6 (10 ng/mL, P < .0001) and V8 (10 ng/mL, P < .001) compared to V2. No change in the placebo-treated group was observed. Blunting of seasonal increases in levels of grass pollen-specific IgE was observed in LPP-treated but not placebo-treated group. LPP immunotherapy, but not placebo, was associated with a reduction in proportions of IL-4 + T H 2 (V6, P = .02), IL-4 + (V6, P = .003; V8, P = .004), and IL-21 + (V6, P = .003; V8, P = .002) follicular helper T cells. Induction of FoxP3 + , follicular regulatory T, and IL-10 + regulatory B cells were observed at V6 (all P < .05) and V8 (all P < .05) in LPP-treated group. Induction of regulatory B cells was associated with allergen-neutralizing IgG 4 -blocking antibodies., Conclusion: For the first time, we demonstrate that the immunologic mechanisms of LPP immunotherapy are underscored by immune modulation in the T- and B-cell compartments, which is necessary for its effect., (Copyright © 2019. Published by Elsevier Inc.)