RecruitingNAINTERVENTIONAL

Effect of Smoking and Time of Day on Eosinophils

This research wants to understand how cigarette smoking and the time of day influence certain immune cells in your blood, called eosinophils. These cells are involved in allergic reactions and asthma. We're looking for healthy people who smoke regularly and also healthy non-smokers. We'll take blood samples in the morning from both groups. For smokers, we'll take samples on two different days – once after not smoking for a few hours, and another time after smoking several cigarettes. This will help us learn more about how smoking directly impacts these important blood cells.

At a glance

Status

Recruiting

Phase

Sponsor

Marek Lommatzsch

Enrolment target

Start

07 Feb 2026

Estimated completion

06 Dec 2026

Healthy

What is this study about?

This study is investigating a specific type of white blood cell in your body called an eosinophil. Eosinophils are part of your immune system and play a role in fighting off certain infections, but they can also be involved in allergic reactions and conditions like asthma. Researchers want to understand if smoking cigarettes has an immediate effect on these cells, and also if the time of day naturally changes their levels.

To figure this out, the study will compare healthy people who smoke regularly with healthy people who don't smoke. Everyone will have blood samples taken at different times in the morning. This allows the researchers to see if there are differences between smokers and non-smokers, and also how an acute period of smoking might alter these cells in smokers. They're hoping to learn more about how smoking impacts your immune system.

Knowing more about the effects of smoking on eosinophils could help doctors better understand various health conditions that involve these cells, potentially leading to new insights into how to help people who smoke.

Key takeaways

This study aims to understand how smoking and time of day affect immune cells called eosinophils.
It involves both healthy smokers and healthy non-smokers.
Participants will have blood samples taken and some breathing tests.
Smokers will attend two separate visits involving different smoking instructions.
The research helps scientists learn more about how smoking impacts the body's immune system.

Who may be eligible?

The study is looking for healthy people to take part. Specifically, they need people who smoke cigarettes regularly and also people who have never smoked.

If you smoke, you need to be generally healthy and smoke at least 8 cigarettes a day. You also need to be between 18 and 50 years old. If you have any ongoing lung problems, or if you've recently been sick or are taking certain medications like steroids or medicines that affect your immune system, you wouldn't be able to join.

Basically, they're looking for active smokers and non-smokers who are otherwise well.

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 between 18 and 50 years old?
Do you currently smoke at least 8 cigarettes a day (if volunteering as a smoker)?
Are you generally healthy, without any long-term lung conditions?
Are you not taking corticosteroids or other immune-suppressing medicines?
Have you been well recently, without any acute illnesses?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll visit the study centre on a few occasions. On each visit, blood samples will be taken in the morning, usually around 8 AM and 12 PM. If you are a smoker, there will be two separate visits, at least 4 weeks apart. On one visit, you'll be asked not to smoke between the morning blood samples. On the other visit, you will be asked to smoke 8 cigarettes between the morning blood samples. For all participants, some basic lung function tests might also be done, and some breathing tests to measure exhaled nitric oxide. The total duration of your involvement could span several weeks, mainly due to the required gap between the smoking and non-smoking measurement days for smokers.

Potential risks and benefits

Taking part in this study may not directly benefit your health, but the information gained could be helpful for future medical knowledge. The main risks involve standard procedures like blood draws, which can cause slight bruising, discomfort, or, rarely, a small infection. You are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

University of Rostock
Verified postcode
Rostock, Germany· Recruiting

Common questions

What are eosinophils?

Eosinophils are a type of white blood cell that's part of your immune system, helping your body fight certain infections and involved in allergic reactions.

Do I need to be a smoker to join?

The study needs both healthy people who regularly smoke and healthy people who have never smoked.

What will happen on the study visits?

You'll have blood samples taken in the morning, and possibly some simple breathing tests. Smokers will have one visit where they don't smoke between morning tests, and another where they do.

How long will the study take for me?

For smokers, your involvement will likely span several weeks, as there's a required break between two specific study visits.

Will I get my test results?

The study description doesn't specify if individual results will be shared directly. You should ask the study team about this.

How to find out more

Marek Prof. Lommatzsch, Prof.

marek.lommatzsch@med.uni-rostock.de +49-381-494-7461 Official trial record

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