Paneez Khoury

Increased sensory nerve density has been described in type 2 inflammatory conditions and is linked to eosinophil and mast cell infiltration and neuropathic pain. To examine these relationships in eosinophilic gastrointestinal diseases, we developed a protocol using Ce3D (clearing-enhanced 3D) tissue clearing to evaluate mucosal gastrointestinal (GI) nerve remodeling and interactions with eosinophils and mast cells in whole-mount GI biopsies. Human gastric and esophageal biopsies were processed for 3-dimensional imaging. Tissues were fixed, permeabilized, and immunolabeled for mucosal nerves (Protein Gene Product 9.5), sensory neurons (substance P), eosinophils (eosinophil peroxidase), mast cells (tryptase), and epithelial cells (pan-cytokeratin). Vacuum-microwave–assisted staining was employed to enhance antibody penetration and protocol efficiency. Samples were cleared with Ce3D and imaged using confocal microscopy. Machine learning–enhanced quantitative analysis and modeling of nerve morphology and cellular interactions, including nerve length, branching, and spatial relationships between eosinophils, mast cells, and sensory neurons were performed. We established a 3-dimensional imaging method for whole-mount GI biopsies to characterize nerve architecture and eosinophil and mast cell interactions in the human esophagus and stomach. This approach enables high resolution and volumetric analyses and can be modified to assess other spatial neuroimmune interactions in human GI mucosal biopsies.

Objective: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, relapsing, inflammatory disease. Management of EGPA predominantly relies on oral corticosteroids (OCS), which are associated with many adverse effects. The phase 3 MIRRA trial demonstrated efficacy and safety of mepolizumab, anti‐interleukin‐5 biologic, for EGPA. This open‐label extension (OLE) of MIRRA assessed long‐term safety and OCS‐sparing effects of mepolizumab.Methods: The OLE (NCT03298061) was a multicenter study that enrolled patients from MIRRA who required OCS ≥5 mg/day up to six months after the end of MIRRA. All patients received mepolizumab 300 mg subcutaneously every four weeks plus standard of care until mepolizumab was discontinued or became approved and reimbursed for EGPA in the respective country. Key outcomes included adverse events (AEs) and use of OCS.Results: One hundred patients were enrolled in the OLE. Mean (SD) and median (min–max) exposure during OLE was 38.5 (27.0) and 27.0 (1.0–89.0) months. On‐treatment AEs were experienced by 98% of patients (43% treatment related; most frequent: injection site reaction [10%]) and serious AEs by 38% of patients (6% treatment related) with no new safety signals versus MIRRA identified. Median (Q1–Q3) OCS dose decreased from 10.0 (7.8–15.0) mg/day at OLE baseline to 5.0 (0.0–10.0) mg/day at study exit. Proportion of patients using OCS >7.5 mg/day decreased from 75% at baseline to 32% at study exit; 28% of patients discontinued OCS.Conclusion: Long‐term use of mepolizumab to treat EGPA was well tolerated and resulted in sustained reductions in OCS use. image

Eosinophil basic biology, including immunoregulatory functions, plays a complex role in a myriad of disorders where eosinophils play a role. Established in vivo and in vitro models and novel emerging techniques for studying eosinophils are integral to parsing the involvement of eosinophils in the pathogenesis of disorders including vasculitis. Knowledge of translational approaches from eosinophil-associated diseases and their application to eosinophilic vasculitis are highlighted. It is becoming increasingly evident that the roles of eosinophils in disease are complex. The use of targeted biological therapies and machine learning has the potential to reveal the contribution of eosinophils in disease pathology.