ClinicalTrials.gov record NCT06270524

Study of the C5a/C5aR1 Axis in IgG4-associated Disease: a Potential Therapeutic Target

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Jul 27, 2026

Pilot Study of the C5a/C5aR1 Axis in IgG4-associated Disease: a Potential Therapeutic Target. C5-MAG4 Study.

About this page. This page shows the study's official ClinicalTrials.gov record ↗, with added help to make it easier to understand. We explain medical terms, highlight key details in plain language, and suggest questions you may want to ask the study team.

The record is periodically copied from ClinicalTrials.gov and may lag behind changes. AI summaries are checked by software, not a clinician.Read moreShow less

The official record is written by the study sponsor and published on ClinicalTrials.gov. It may not always reflect the latest changes. Before making any decisions, please confirm important information with the study team and your own healthcare team.

Where you see "AI summary", AI was used to create a plain-language explanation and software checked it against the source. It has not been reviewed by a clinician, so it may contain mistakes or leave out important details.

StatusNot yet recruitingThe study has been registered but has not started enrolling. Sites and contacts may not be listed yet.The registry record was last updated on Jun 26, 2024, about 2 years ago, so the status shown may be out of date. The study team or the registry can confirm.

Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.

Healthy volunteersAcceptedPeople who do not have the condition being studied who are allowed to take part. Some studies include both people with the condition and healthy volunteers; others may enrol only healthy volunteers.

Age18 years old and older

SexAll

AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This study compares blood markers of the C5a–C5aR1 pathway in people with active IgG4-associated disease, people with IgG4-associated disease in remission, and healthy volunteers. Participation involves giving blood samples for laboratory analysis; the study is cross-sectional and compares the three groups. Key eligibility gates include adults (age >18); exclusion of those on recent systemic corticosteroids (systemic corticosteroid treatment ≥5 mg/day ongoing or <1 month), recent immunosuppressive therapy (ongoing or <3 months), or recent biotherapy (current or <6 months). Healthy volunteers are excluded if they had an infectious episode in the past 30 days or have known inflammatory/autoimmune disease.

What it is studying. Whether the C5a–C5aR1 axis differs in people with active IgG4-associated disease compared with people in remission and with healthy people, by measuring serum C5a and the frequency of C5aR1+ and TGF‑β+ monocytes in blood.

What the researchers hope to learn. To identify abnormalities in the C5a–C5aR1 pathway and related monocyte changes in IgG4-associated disease, and to find cellular or molecular targets that could inform future therapeutic research.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

This is a monocentric, comparative, cross-sectional, case-control study seeking to identify abnormalities of the C5a-C5aR1 axis between a population of patients with active IgG4-associated disease (MAG4) and two control groups: healthy subjects without MAG4 and patients with MAG4 in remission.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Procedure: Blood sampling

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

for patients suffering from IG4-related disease and patients in remission :
age > 18
diagnosis of IgG4-associated disease according to ACR/EULAR 2019 classification criteria (4,5) with a score ≥20.
disease activity score (IgG4-RD Responder Index) ≥2 in at least one affected organ

Exclusion criteria

for patients suffering from IG4-related disease and patients in remission :
presence of a differential diagnosis ("IgG4-RD mimicker") or exclusion criterion according to ACR/EULAR 2019 classification criteria (4,5).
systemic corticosteroid treatment ≥5 mg/day ongoing or < 1 month ; Study C5-MAG4_RCAPHM21_0433 Protocol Version 1.1 of 16/01/2024 Page 15 of 41
immunosuppressive therapy ongoing or < 3 months ;
current biotherapy treatment or < 6 months;
absence of signed informed consent;
absence of affiliation to a Social Security scheme.
patient participating in an ongoing therapeutic trial ;
any condition which, in the opinion of the investigator, could influence the results of the study.
Inclusion criteria for healthy volunteers :
age > 18
Exclusion criteria for healthy volunteers :
infectious episode (temperature >38°C, flu-like signs) in the 30 days prior to inclusion;
known inflammatory (including IG4-related disease) or autoimmune pathology;
treatment with corticosteroids in progress or taken in the month prior to sampling, or immunosuppressants in progress or taken in the 3 months prior to sampling, or biotherapy in the 6 months prior to sampling;
absence of signed informed consent;
absence of affiliation to a Social Security scheme;
persons taking part in an ongoing therapeutic trial;
any condition which, in the opinion of the investigator, could influence the results of the study.

Study description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Detailed description from the registry

IgG4-associated disease is a rare fibrosing and inflammatory disorder whose pathophysiology remains poorly understood. Activation of certain monocyte/macrophage populations (in particular M2-type macrophages) has been shown to be involved during the course of the disease. The mechanisms behind this monocyte/macrophage activation are not known. Expression of the C5aR receptor on the surface of these populations, and preliminary findings of elevated C5a in these patients, suggest a potential role for this C5a-C5aR axis. Demonstration of the involvement of this pathway would open a path to therapeutic perspetives (C5aR inhibitors) for these patients, who frequently suffer from cortico-dependence and relapses. The aim of this research is to use healthcare technologies to identify cellular and molecular therapeutic targets in the context of the IgG4-associated disease

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants must sign informed consent and will provide blood samples for laboratory analysis. The registry lists only blood sampling as the study procedure; no other specific procedures, number of visits, or follow-up schedule are described in the record.

How the study is structured. A single-center, non-randomized, parallel case-control (cross-sectional) interventional study. Three groups (active IgG4‑RD, IgG4‑RD in remission, and healthy volunteers) give blood samples that are compared; there is no masking. The primary and secondary outcomes are lab measurements made on those blood samples.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

The registry says recruitment has not started. When is it expected to open, and can I register interest now?
No sites are listed on the registry yet. Where will the study take place?
Which of the eligibility criteria would need to be checked with tests before I could join?

More on IgG4-related disease

Clinical trials32 trials listed for IgG4-related diseaseEvery trial the registry lists for IgG4-related disease, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in IgG4-related disease researchLatest monthly update: September 2026. Includes: Relapse prevention trial. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start: Sep 1, 2024 (estimated)
Primary completion: Sep 1, 2026 (estimated)
Study completion: Apr 30, 2027 (estimated)
Target enrollment: 66 participants (estimated)
Last updated on registry: Jun 26, 2024
Data verified: Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor: Assistance Publique Hopitaux De Marseille

Participating sites

Study locations have not been posted on ClinicalTrials.gov yet. This study is not yet recruiting, so sites may be added when recruitment begins.

Terms used on this page · explanations by MedicalUpdates.ai

corticosteroid: Steroid medicines, such as prednisone, that reduce inflammation. Studies often require a stable dose at entry or measure whether the study treatment allows the dose to be reduced.
immunosuppressive: A medicine that reduces the activity of the immune system. Studies of autoimmune conditions often require a stable dose, a prior failure, or a washout of such medicines.
informed consent: The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
Inclusion criteria: The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion criteria: The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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