RecruitingNAINTERVENTIONAL

Immunological Effects of Iron Supplementation in HHT Disease

This study is for people with a rare genetic condition called Hereditary Haemorrhagic Telangiectasia (HHT). People with HHT often have nosebleeds, visible tiny blood vessels, and sometimes problems with blood vessels in organs like the lungs or gut. Many also have low levels of certain immune cells called T lymphocytes, and a higher risk of some infections, though we don't fully understand why. HHT patients also commonly develop iron deficiency anaemia and need iron supplements. We've noticed a link between how much iron treatment someone has and their T lymphocyte levels. This study aims to find out if low iron itself, or iron supplements, affect the immune system in HHT patients. Understanding this better could help improve care and reduce infection risks for people living with HHT.

At a glance

Status

Recruiting

Phase

Sponsor

Hospices Civils de Lyon

Enrolment target

155

Start

24 Sep 2025

Estimated completion

31 Dec 2028

Hereditary Haemorrhagic Telangiectasia

What is this study about?

If you have Hereditary Haemorrhagic Telangiectasia, often called HHT, you might be familiar with symptoms like frequent nosebleeds or tiny red spots on your skin. These happen because HHT affects your blood vessels. What you might not know is that many people with HHT also have fewer immune cells, specifically T lymphocytes, which are important for fighting infections. We've also observed that HHT patients can be more prone to certain infections, like brain abscesses if they have lung vessel problems, or bone and joint infections if they've had long-term nosebleeds.

Another common issue for people with HHT is iron deficiency anaemia, affecting about half of patients. This often requires ongoing iron treatment, either as tablets or through a drip. Interestingly, we've seen a connection between the amount of iron treatment a patient receives and the number of their T lymphocytes. This link is a bit of a mystery, and it could be due to a couple of reasons. It might be that iron treatments themselves have an effect on the immune system, or it could be that the underlying iron deficiency is what impacts immune cells, and the treatment levels just reflect how severe that deficiency is.

This study has been designed to help us solve this puzzle. By looking closely at the immune system in HHT patients, particularly those with different iron levels and treatments, we hope to understand exactly how iron deficiency and iron supplements affect their T lymphocytes and overall immune health. This knowledge is important because it could lead to better ways to manage HHT, reduce infection risks, and ultimately improve the health and well-being of people living with the condition.

Key takeaways

This study investigates iron's effect on the immune system in HHT patients.
It aims to understand why some HHT patients have fewer T lymphocytes and higher infection risks.
Participation involves two blood tests over three months, with no new medications.
Results could lead to better management and reduced infection risks for HHT.
Only adults with diagnosed HHT and specific genetic findings can join.

Who may be eligible?

This study is looking for adults aged 18 to 99 who have been diagnosed with HHT. To join, your HHT diagnosis must meet specific medical criteria and your genetic test results must show a change in one of the specific genes linked to HHT (ENG, ACVRL1, or MADH4). You also need to be part of an ongoing study called CIROCO and have had routine blood tests for HHT within the last two weeks.

The study divides people into three different groups based on their iron levels and recent iron treatments. For example, some groups will include people with normal iron levels who haven't had iron supplements or blood transfusions recently. Other groups will include people with normal iron levels who are currently taking iron or have had recent iron treatments. The third group is for people with low iron levels who haven't had recent iron supplements or transfusions.

However, you won't be able to join if your haemoglobin (a measure of red blood cells) is very low (below 90 g/L). You also cannot participate if you have cancer or have recently recovered from it, or if you have an active infection or recently recovered from one (within the last three months). People with certain autoimmune conditions needing specific medications, pregnant or breastfeeding women, minors, or those unable to give their consent freely (for example, if under legal protection or in psychiatric care) are also not eligible.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you an adult aged 18 or over with HHT?
Has your HHT diagnosis been confirmed by specific genetic tests?
Are you currently part of the CIROCO study?
Have you had routine HHT blood tests in the last two weeks?
Are you able to provide your full consent to join the study?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, it would involve providing two blood samples. The first blood sample would be taken at the very start of the study. The second blood sample would be taken three months later. There are no other required visits or extra procedures beyond these two blood tests. You won't be given any new medications specifically for this study. The total duration of your involvement in the study would be approximately three months, from your first blood test to your second.

Potential risks and benefits

Taking part in this study won't directly improve your HHT condition, as we are mainly gathering information. However, your participation will be very valuable in helping doctors better understand how iron and the immune system are connected in HHT patients. This could lead to improved treatments and care for HHT in the future. The main risks are minor discomfort or bruising from the blood tests. You are free to withdraw from the study at any time, for any reason, without it affecting your usual medical care.

Locations (1)

Hôpital Femme-Mère-Enfant
Verified postcode
Bron, France· Recruiting

Common questions

What is HHT?

HHT (Hereditary Haemorrhagic Telangiectasia) is a rare genetic condition that affects blood vessels, often causing nosebleeds and small red spots on the skin, and sometimes affecting organs like the lungs or gut.

Why is iron important in HHT?

Many people with HHT develop iron deficiency anaemia due to blood loss from nosebleeds or other areas, and often need iron supplements. This study wants to see how iron levels and iron treatments might affect their immune system.

What are T lymphocytes?

T lymphocytes are a type of white blood cell, an important part of your immune system that helps your body fight off infections. People with HHT sometimes have lower levels of these cells.

Will I receive any new treatment in this study?

No, you will not receive any new or experimental treatments as part of this study. It only involves blood tests to gather information.

How long will my involvement in the study last?

Your involvement in the study will last about three months, during which you'll have two blood tests.

How to find out more

Alexandre Guilhem, MD

alexandre.guilhem@chu-lyon.fr 04 27 85 50 40 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.