Effects of everyday allergen and skin, airway, and gut exposures on inflammation and barrier health

THREAT: Testing Harms Related to Exposure to Allergenic and Epithelial Toxins

This study will test whether everyday exposures from common skin and hair products, processed foods, and air change inflammation and barrier health in healthy adults aged 18 to 80.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 120 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: National Institutes of Health Clinical Center (CC) (NIH)
• Drugs / interventions: chemotherapy
• Locations: 1 site (Bethesda, Maryland)
• Trial ID: NCT07271381 on ClinicalTrials.gov

What this trial studies

In a randomized crossover design, healthy adults will spend two inpatient stays of up to seven days each in a controlled environment with either common (typical Western) exposures or cleaner, 'pure' exposures, with a 4–6 week washout between stays. Participants are block-randomized within cohorts focused on skin, gastrointestinal, or airway outcomes and will use only provided foods and personal-care products while confined. Investigators will collect biospecimens and measure skin impedance, microbiome samples, and airway and GI parameters to detect short-term changes linked to exposure conditions. The protocol aims to connect real-world lifestyle and product exposures to measurable changes in inflammation and barrier function.

Who should consider this trial

Good fit: Healthy adults aged 18–80 who can provide consent, tolerate two inpatient stays of up to seven days, follow provided diets and product use, and have no diagnosed atopic, autoimmune, metabolic, chronic infectious, or inflammatory conditions.

Not a fit: People with physician-diagnosed asthma, atopic dermatitis, food allergy, chronic hives, autoimmune or other chronic inflammatory or infectious diseases, recent cancer, a positive Phadiatop test, or current medications that affect the skin/GI/airway microbiomes are excluded and unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the study could identify everyday exposures that contribute to inflammation and suggest practical changes in products or diet to reduce allergic and inflammatory risk.

How similar studies have performed: Epidemiologic and smaller controlled studies have suggested links between environmental exposures, diet, and inflammation, but using a controlled inpatient crossover design to test real-world product and food exposures is relatively novel.

Eligibility criteria

* INCLUSION CRITERIA:

To participate in this study, an individual must meet all of the following criteria:

1. Ability to provide informed consent.
2. Age 18-80 years.
3. Agreement to adhere to lifestyle considerations.
4. Ability to exclusively adhere to UPD and MPD during inpatient stay.
5. Ability to speak English.
6. Willing to allow storage of samples and data for future research.

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Diagnosis of atopic (physician-diagnosed asthma, AD, food allergy, chronic hives), autoimmune, metabolic, or chronic infectious or inflammatory diseases.
2. Positive Phadiatop test.
3. Current or history of neoplastic disease within 5 years.
4. Use of medication(s) that may affect skin, GI, and/or airway symptoms and may have an effect on skin microbiome, GI microbiome (topical or oral antibiotic use may require 3-6 month delay in enrollment for gut microbiome repopulation, see #8), and/or serum cytokines (other than oral birth control, which is not exclusionary and is allowed during participation provided there is consistence use for 3-6 months prior to enrollment).
5. Current receipt of chemotherapy.
6. HIV, hepatitis B, or hepatitis C infection.
7. Receipt of any vaccine within 1 month prior to enrollment.
8. Receipt of oral antibiotics within 3-6 months prior to enrollment.
9. Use of topical, oral, or parental corticosteroids within 1 month prior to enrollment.
10. Participation in another treatment or intervention study within 3 months prior to enrollment.
11. Currently pregnant or lactating.
12. Currently smoking or vaping.
13. Any other condition or intercurrent illness deemed by the investigators to be of potential risk to the participant or validity of study results.

Where this trial is running

Bethesda, Maryland

• National Institutes of Health Clinical Center — Bethesda, Maryland, United States (Recruiting)

Study contacts

• Principal investigator: Hirsh D Komarow, M.D. — National Institute of Allergy and Infectious Diseases (NIAID)
• Study coordinator: Jodi L Blake, R.N.

Conditions Allergic; Inflammatory; Environmental Exposures; Skin barrier dysfunction; Skin impedance