Macrophages, GM-CSF and MARS Proteinosis

Genetic Mutation Clinical Trial

— MacroMARS  

Official title:

Study of Macrophage Function and of the GM-CSF Signaling Pathway in Alveolar Proteinosis by Mutations of the MARS Gene

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04811274
• Other study ID #: APHP201476
• Secondary ID: 2020-A02750-39
• Status: Recruiting
• Start date: June 7, 2021
• Est. completion date: June 7, 2024

Study information

• Verified date: June 2021
• Source: Assistance Publique - Hôpitaux de Paris
• Contact: Alice HADCHOUEL, MD, PhD
• Phone: 1 44 49 48 47
• Email: alice.hadchouel-duverge[@]aphp.fr
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

Mutations in the MARS gene encoding methionyl-tRNA synthetase are responsible for a genetic form of alveolar proteinosis (PAP), but the pathophysiological mechanisms of the respiratory phenotype are not known. The main hypothesis is that the PAP phenotype in these patients is secondary to a defective clearance of the surfactant by the alveolar macrophages. The main objective of the study is to study the clearance capacity of lipoproteinaceous material by macrophages of patients with MARS related PAP. This will be investigate in cultured macrophages derived from peripheral blood monocytes of patients (patients with MARS related PAP) and controls (patients without MARS related PAP).

Description:

Pulmonary alveolar proteinosis (PAP) is a rare respiratory disease characterized by the accumulation of lipoproteinaceous material within the pulmonary alveoli, resulting in the majority of cases from a defective clearance of the surfactant by intra-alveolar macrophages. Mutations in the MARS gene encoding methionyl-tRNA synthetase are responsible for a genetic form of alveolar proteinosis, but the pathophysiological mechanisms leading to mutations in the respiratory phenotype are not known. The main hypothesis is that the alveolar proteinosis phenotype in these patients is secondary to a defective clearance of the surfactant by the alveolar macrophages. The main objective of the study is to study the clearance capacity of lipoproteinaceous material by macrophages of patients with MARS related PAP. This will be investigate in cultured macrophages derived from peripheral blood monocytes of patients (patients with MARS related PAP) and controls (patients without MARS related PAP). The subjects and the controls will be included during a hospitalization during which a blood sample and a bronchoscopy with broncoalveolar lavage must be performed as part of their care.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 20
• Est. completion date: June 7, 2024
• Est. primary completion date: June 7, 2024
• Accepts healthy volunteers: No
• Gender: All
• Age group: N/A to 17 Years

Eligibility

Inclusion Criteria:

• Minors from 0 to 17 years hospitalized for their care at Necker Enfants Malades hospital and for whom a blood sample and a bronchoscopy with bronchoalveolar lavage must be performed as part of their care
• Information and consent of the holders of parental authority and the patient

Exclusion Criteria:

• Refusal of holders of parental authority or patient

Related Conditions & MeSH terms

• Genetic Mutation
• MARS
• Pulmonary Alveolar Proteinosis
• Pulmonary Alveolar Proteinosis (PAP)

Intervention

Biological:
• Blood collection
2 to 5 ml
• Bronchoalveolar lavage fluid collection
5 to 25 ml

Locations

Country	Name	City	State
France	Hôpital Necker-Enfants Malades	Paris

Sponsors (1)

Lead Sponsor	Collaborator
Assistance Publique - Hôpitaux de Paris

Country where clinical trial is conducted

France, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Measurement of the clearance	Measurement of the clearance of abnormal lipo-proteinaceous material (from patients) at 48h of culture by cultured macrophages derived from peripheral blood monocytes from patients and controls.; Microscopic examination of cell samples prepared on slide after cytospin and stained with oil red'O.	Day 0
Secondary	Measurement of the clearance after supplementation with methionine	Measurement of the clearance of abnormal lipo-proteinaceous material (from patients) at 48h culture with methionine supplementation in culture medium by cultured macrophages derived from peripheral blood monocytes from patients and controls.; Microscopic examination of cell samples prepared on slide after cytospin and stained with oil red'O.	Day 0
Secondary	Cellular phenotyping and study of the GM-CSF pathway	Description : Study the impact of mutations on the cell phenotype and the GM-CSF signalling pathway.; (i) CD11b and CD49d cell immunostaining which are surface markers of healthy alveolar macrophages ; (ii) measurement of the level of intracellular phosphorylation of STAT5 by flow cytometry; and (iii) measurement of the level of expression of the SPI1, PPAR? and ABCG1 genes by quantitative PCR.; These measurements will be performed in cultured macrophages derived from peripheral blood monocytes of patients and controls, but also in alveolar macrophages directly isolated from the BAL fluid of patients and controls. All these measurements will be performed in response to incubation with GM-CSF.	Day 0