Modulation of Cellular, Molecular, and Humoral Responses by PQ Grass 27,600 SU for the Treatment of Seasonal Allergic Rhinitis - A Randomised Double Blind Placebo Control Exploratory Field Study

Q: What was the main aim of this study on PQ Grass for seasonal allergic rhinitis?

To investigate the immunological mechanisms induced by PQ Grass across conventional and extended treatment regimens.

Q: How were participants assigned in the randomised double-blind placebo-controlled exploratory field study?

Participants received either conventional PQ Grass (six once-weekly injections), extended PQ Grass (three once-weekly followed by three once-monthly injections), placebo with microcrystalline tyrosine (MCT), or saline placebo.

Q: What immunological changes did PQ Grass regimens produce compared with placebo groups?

Both regimens improved total combined scores and increased the sIgG4/sIgE ratio, while inducing IgA1 and IgA2, with functional blocking antibodies noted in nasal fluid and serum.

Sep 29, 2026

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Seasonal allergic rhinitis treatment using PQ Grass is clinically effective, but the immunological mechanism is not well defined. This randomised, double-blind, placebo-controlled exploratory field study compared conventional and extended pre-seasonal regimens versus placebo with microcrystalline tyrosine or saline. Humoral, cellular, and molecular responses were evaluated at baseline, end of treatment, before season, and end of season. Both regimens improved total combined scores and increased sIgG4/sIgE, with IgA1 and IgA2 induction, supporting tolerance-related immune modulation.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

Background

Methods

Results

Conclusions

Trial Registration

Introduction

Allergy ORIGINAL ARTICLE OPEN ACCESS Rhinitis, Sinusitis and Upper Airway Disease Modulation of Cellular, Molecular, and Humoral Responses by PQ Grass 27,600 SU for the Treatment of Seasonal Allergic Rhinitis: A Randomised Double Blind Placebo Control Exploratory Field Study Janice A. Layhadi1 | Sviatlana Starchenka2 | Pieter-Jan De Kam2 | Elizabeth Palmer1 | Lily Y. D. Wu1 | Sean T. Keane1 | William T. Fulton1 | Prista Hikmawati1 | Xun Meng1 | Paulina Filipaviciute1 | Anna Cutrina Pons1 | Kemi Oluwayi2 | Katarzyna Lis2,3 | Oliver Armfield2 | Murray A. Skinner2 | Matthew D. Heath2 | Simon J. Hewings2 | Matthias F. Kramer2,3 | Mohamed H. Shamji1 1National Heart and Lung Institute, Imperial College London, London, UK | 2Allergy Therapeutics PLC, Worthing, UK | 3Bencard Allergie GmbH, Munich, Germany Correspondence: Mohamed H. Shamji ([m.shamji@imperial.ac.uk](m.shamji@imperial.ac.uk)) Received: 23 August 2024 | Revised: 7 April 2025 | Accepted: 19 April 2025 Funding: This work was supported by Allergy Therapeutics. Keywords: allergy treament | basic mechanisms | immune tolerance | immunotherapy and tolerance induction | immunotherapy clinical | immunotherapy vaccines and mechanisms | T cells ABSTRACT Background: A short-course pre-seasonal subcutaneous injection of PQ Grass is clinically effective for the treatment of allergic rhinitis, though its mechanism remains unclear. The aim of the study was to interrogate immunological mechanisms induced by PQ Grass conventional and extended regimens. Methods: A RDBPC exploratory field study involving participants that either received injections of PQ Grass with a cumulative dose of 27,600 SU conventional (six once weekly injections) or extended regimen (three once weekly injections followed by three once monthly injections) or placebo containing microcrystalline tyrosine (MCT) (placebo + MCT) or saline (placebo) was performed. Humoral, cellular, and molecular responses were assessed at baseline (V1), end of treatment, prior to grass pollen season (V12) and end of pollen season (V15) . Immunoglobulin analyses and cellular/gene microarray analyses were performed in the sub-study cohort consisting of PQ Grass Conventional (n = 25 and n = 10, respectively), PQ Grass Extended (n = 26 and n = 10, respectively), Placebo with MCT (n = 13 and n = 5, respectively), and Placebo (saline; n = 12 and n = 5, respectively) . Results: Both PQ Grass regimens, conventional and extended, were associated with improvement in total combined scores (TCS) with a relative difference of −35.0%(p = 0.03) and −40.8%(p = 0.01) against placebo with MCT, respectively. Both PQ Grass treatment regimens were associated with increases in the sIgG4/sIgE ratio (all, p < 0.05) and induction of IgA1 (all, p < 0.05) and IgA2 (all, p < 0.01) compared to placebo groups. Nasal fluid (p < 0.01) and serum (p < 0.05) blocking antibodies are functional and | Abbreviations: AIT, allergen immunotherapy; AR, allergic rhinitis; BAT, Basophil activation test; Breg, B regulatory cells; CPT, conjunctival provocation test; CSMS, combined symptom and medication score; dMS, daily medication score; dSS, daily symptom score; ELISA, enzyme linked immunosorbent assay; GPS, grass pollen season; IL, interleukin; MC, metacluster; MCT, microcrystalline tyrosine; MPL, monophosphoryl Lipid-A; PBMC, peripheral blood mononuclear cells; RDBPC, randomised double blind placebo control studies; SAR, seasonal allergic rhinitis; SCIT, subcutaneous immunotherapy; sIgA1, specific immunoglobulin A1; sIgA2 , specific immunoglobulin A2; sIgG4, specific immunoglobulin G4; SLIT, sublingual immunotherapy; SOM, self-organising maps; SU, standardised unit; TCS, total combined score; Tfh, T follicular helper cells; Th2, T helper 2 cells; Th2A, allergen-specific Th2 cells; Treg, T regulatory cells; TSS, total symptom score.
Janice A. Layhadi, Sviatlana Starchenka, and Pieter-Jan De Kam contributed equally to this work. |

FAQs

What was the main aim of this study on PQ Grass for seasonal allergic rhinitis?

To investigate the immunological mechanisms induced by PQ Grass across conventional and extended treatment regimens.

How were participants assigned in the randomised double-blind placebo-controlled exploratory field study?

Participants received either conventional PQ Grass (six once-weekly injections), extended PQ Grass (three once-weekly followed by three once-monthly injections), placebo with microcrystalline tyrosine (MCT), or saline placebo.

What immunological changes did PQ Grass regimens produce compared with placebo groups?

Both regimens improved total combined scores and increased the sIgG4/sIgE ratio, while inducing IgA1 and IgA2, with functional blocking antibodies noted in nasal fluid and serum.

Sep 29, 2026

Uploaded by Fans