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NCT Number: NCT07625111

Effect of Smoking and Time of Day on Eosinophils

The study investigates the effect of acute smoking and time of day on blood eosinophils in chronic smokers. Chronic cigarette smokers without chronic respiratory diseases smoking at least 8 cigarettes per day and never-smoking controls are examined. Blood eosinophil counts and surface molecules are measured at 8 and 12 am in both groups. In smokers, two measurements are performed (at least 4 weeks apart): one measurement with no smoking between 8 and 12 am, and another measurement with smoking of 8 cigarettes between 8 and 12 am.

Recruiting

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Key information

Conditions

Healthy Behavior Smoking

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

20 chronic cigarette smokers without chronic respiratory diseases smoking at least 8 cigarettes per day and 20 never-smoking controls are recruited. Blood eosinophil counts and surface molecules are measured at 8 and 12 am in both groups. In smokers, two measurements are performed (at least 4 weeks apart, cross-over design): one measurement with no smoking between 8 and 12 am, and another measurement with smoking of 8 cigarettes between 8 and 12 am. The effects of the time of day (comparing 8 and 12 am) and the effects of acute smoking (comparing the effects of no smoking or acute smoking at 12 am) on blood eosinophil counts and surface molecules (using flow cytometry) are analyzed. Additional parameters examined: lung function, exhaled nitric oxide, total and specific IgE in serum.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy current smokers
  • Age between 18-50 years
  • Smoking of at least 8 cigarettes/day

Exclusion criteria

  • Chronic respiratory diseases
  • Any treatment with corticosteroids or other immunosuppressants
  • Any acute illness

Treatment and study plan

Smoking for 4 hours

Other

Smoking of 8 cigarettes in 4 hours

Primary outcomes

  1. Blood eosinophil counts

    Time frame: 8 am (baseline) and 12 am (follow-up after intervention)

    Blood eosinophil counts in cells/µl blood

Secondary outcomes

  1. Blood eosinophil surface molecules

    Time frame: 8 am (baseline) and 12 am (follow-up after intervention)

    Blood eosinophil surface molecules (such as CD62L or CD294), measured using flow cytometry

Study contacts

Contact information is provided by the study sponsor or research team.

Johann C. Virchow, Prof.

CONTACT

+49-381-494-7461

Marek Prof. Lommatzsch, Prof.

CONTACT

[email protected]

+49-381-494-7461

Sponsors and collaborators

Lead sponsor

Marek Lommatzsch

Other

Registry information

Official study title

Effects of Acute Smoking and Time of Day on Blood Eosinophils in Humans

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 4, 2026
Registry last updated
Jun 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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