Modeling Bronchial Epithelium in Severe Asthma With Human Induced Pluripotent Stem Cells (iPSC)

Modeling Bronchial Epithelium in Severe Asthma With Human Induced Pluripotent Stem Cells (iPSC)

Asthma is severe when it cannot be controlled with maximum-dose inhaled therapies while management of comorbidities and other precipitating or aggravating factors has been optimized. Allergic bronchopulmonary aspergillosis (ABPA) is a complex bronchopulmonary disease resulting from immunological reactions against Aspergillus Fumigatus.

The development of a model of bronchial epithelium generated from patients with chronic lung disease will allow the modeling of bronchial tissue to understand the formation of these mucus plugs. This study aims to validate this model

The investigators propose to verify the feasibility of obtaining and comparing two epithelia in two populations based on the following experiments:

Differentiation of an Induced Pluripotent Stem cell (iPSC) clone derived from blood sample (Peripheral Blood Mononuclear Cells) of Type 2 inflammation (T2) severe asthma and Allergic Bronchopulmonary Aspergillosis (ABPA) in order to obtain differentiated bronchial epithelia in vitro.

Asthma is severe when it cannot be controlled with maximum-dose inhaled therapies while management of comorbidities and other precipitating or aggravating factors has been optimized. Allergic bronchopulmonary aspergillosis (ABPA) is a complex bronchopulmonary disease resulting from immunological reactions against Aspergillus Fumigatus.

At the cellular and molecular level, severe asthma and ABPA are chronic bronchial diseases characterized by type 2 (T2) airway inflammation, bronchial smooth muscle hyperplasia, excessive mucus production by mucus cell metaplasia and epithelial remodeling. Type 2 inflammation in asthma is predominant and is characterized by the accumulation of immune cells, such as eosinophils, mast cells, T-helper 2 (Th2) cells, innate lymphoid cells type 2 (ILC2s) and dendritic cells.

Persistent airway obstruction despite maximal therapy is currently considered the greatest unmet medical need in asthma treatment. Fahy and colleagues published a key paper in 2018 that may explain airway obstruction. Using chest CT scans, they demonstrated the presence of mucus plugs that completely occlude segments of the airways of severe asthmatics. These mucus plugs are associated with a high number of circulating eosinophils in the blood.

There is no large-scale model to model severe asthma and ABPA. The investigators propose to develop a bronchial epithelium with pluripotent stem cells (iPSC) in air-liquid interface called iALI generated from these patients in aim to model severe asthma and ABPA and in particular the epithelium.

The secondary objectives aims to answer are:

• Comparison of the iPSC derived airway epithelium with nasal epithelial cells isolated from the same patient (nasal brush).
• To characterize the phenotype of the iPSC derived airway epithelium from ABPA and T2 severe asthma patient, in comparison to a healthy control.
• Differentiation of iPSC into mature eosinophils
• Co culture of the epithelia with iPSC derived eosinophils
• Culture of iPSC derived airway epithelium with Charcot-Leyden crystal
• Demonstrate the feasibility of obtaining iPSC from peripheral blood sampling.

Inclusion Criteria:

- Smoking < 10 BP and weaned > 1 year.

Diagnostic criteria for Severe asthma group T2 :

• History of severe asthma diagnosed by a physician (according to GINA criteria)
• Subject on high dose inhaled corticosteroid (ICS 1000 µg beclometasone equivalent) and beta-agonists for at least 6 months prior to inclusion
• Blood eosinophilia in history (previous years) > 300/mm3

Diagnostic criteria for Allergic bronchopulmonary aspergillosis (ABPA) group

- Diagnosis of ABPA defined by the following 3 mandatory criteria:

1. Diagnosis of asthma by the physician for at least 12 months based on the 2019 recommendations of the Global Initiative for Asthma (GINA) group
2. Evidence of hypersensitivity to Aspergillus Fumigatus by skin test (on screening or previous documented positive skin test within the last 12 months), or serum Immunoglobulin E (IgE) specific antibodies to A. Fumigatus (≥ 0.35 kUnit/l) at screening.
3. Elevated total serum IgE (> 1000 IU/ml). If the 3 ancillary criteria for the diagnosis of of ABPA (below) are met, an IgE level ≤ 1,000 IU/ml is acceptable. If the patient is receiving oral corticosteroids (OCs) at screening, a previous documented IgE level >1000 IU/ml within the last 12 months is acceptable.

And at least 2 of the following ancillary criteria:

1. Blood eosinophil count >500 cells/μl at screening for patients not receiving OCs at screening. For patients receiving OCs at screening, blood eosinophil count > 500 cells/μl at screening or documented previous eosinophil count > 500 cells/μl in the last 12 months.
2. Presence of precipitating antibodies or serum immunoglobulin G (IgG) to A. Fumigatus at screening.
3. Documented radiological abnormalities consistent with ABPA (such as transient mucoid impaction, hyperdense mucus [high attenuation of mucous plugs], opacities of centro-lobular nodules attenuation of mucous plugs], opacities of centro-lobular nodules, telectasis, bronchiectasis, etc.) by chest X-ray or high-resolution computed tomography (HR-CT) within the last 18 months or at screening.

Exclusion Criteria:

• Other associated respiratory diseases (e.g. chronic obstructive pulmonary disease (COPD), cystic fibrosis)
• Patient in an exclusion period determined by another protocol
• Protected populations according to the French public health code: Parturient, nursing or pregnant women; subjects deprived of liberty by judicial or administrative decision; Major protected by law (under any form of guardianship).
• Lack of informed consent
• Non-beneficiary of the national health insurance system