Skin ImmunitySIAPNCT07291193
Impact of Sex Hormones on Human Skin Immunity in Health and Hidradenitis Suppurativa (SIAP)
An observational study of Skin Immunity, run by Institut Pasteur.
Trial summary
Sex hormones are major regulators of skin immunity. Pregnancy represents a unique physiological state of profound hormonal remodeling. In late pregnancy, maternal levels of estrogens, progesterone, and other hormones increase dramatically, offering an unparalleled model to study the impact of sex hormones on skin… Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Skin Immunity
- What is being tested?
- Blood sample, skin microbiota and biopsy
- Type of treatment
- Surgery or procedure
- How many people
- 240 participants
- Where
- No sites listed yet
- Study dates
- Jan 2026to Mar 2031
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: As part of this study, adults (pregnant women, non-pregnant women, and men), healthy (not affected by HS) and affected by HS, will be recruited.
Who may be able to join
- Common criteria :
- Subject>18 years and <45 years,
- Written informed consent of the subject,
- Subject affiliated to the Assurance Maladie (French Health System) except Aide Médicale d'Etat (French State Medical Aid),
- Subject agrees that genomic analyses may be carried out on the samples
- Specific criteria :
- For pregnant women:Third trimester of pregnancy (between 29-37 weeks of amenorrhea).
- For HS subjects: Subject with hidradenitis suppurativa lesions at the sampling sites.
Who cannot join
- Common criteria :
- Subject immunocompromised,
- Subject under legal protection (guardianship or curatorship),
- Subject is unable to provide informed consent and to comply with the study requirements due to geographical, social, or psychiatric reasons,
- Subject in other research whose procedures may influence the immune system,
- Contraindication to any of medications listed in section 5.1 (antiseptic and local anesthetic used for biopsy(ies)),
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- Subject whose health condition does not permit participation in study procedures.
- Specific criteria :
- For no HS subjects : Scarred skin at the biopsy site, Subject with pre-existing and/or still active inflammatory skin conditions, Subject experiencing early menopause (women) or andropause (men).
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Impact of Sex Hormones on Human Skin Immunity in Health and Hidradenitis Suppurativa
Sex hormones are major regulators of skin immunity. Pregnancy represents a unique physiological state of profound hormonal remodeling. In late pregnancy, maternal levels of estrogens, progesterone, and other hormones increase dramatically, offering an unparalleled model to study the impact of sex hormones on skin immunity. Hidradenitis suppurativa (HS) provides a clinically relevant model to examine how sex hormones modulate skin inflammation.
Read the detailed description
Sex hormones are major regulators of skin immunity. Recent work from Belkaid's laboratory in mice demonstrated that testosterone negatively regulated skin innate lymphoid cells (ILC2), leading to a reduction in dendritic cell accumulation and decreased activation in males, along with reduced tissue immunity. These findings highlight that sex-related differences in skin immunity emerge primarily after sexual maturation, driven by fluctuating hormone levels. However, whether these mechanisms are conserved in humans remains unknown.
Pregnancy represents a unique physiological state of profound hormonal remodeling. In late pregnancy, maternal levels of estrogens, progesterone, and other hormones increase dramatically, offering an unparalleled model to study the impact of sex hormones on skin immunity. Understanding maternal skin immunity is of particular importance, as the maternal immune system must balance tolerance to the fetus with protection against pathogens. Perturbation in this balance can have lasting effects on both maternal and child health. Faced with the dramatic increase in inflammatory and autoimmune disorders affecting children globally, understanding maternal immunity is of fundamental importance.
Hidradenitis suppurativa (HS) provides a clinically relevant disease model to examine how sex hormones modulate skin inflammation. HS is a chronic inflammatory skin disease with strong sex dimorphism: it affects predominantly women (70%) in Europe but is often more severe in men. In women, HS severity varies with the menstrual cycle and is frequently altered during pregnancy, suggesting a hormonal component in disease modulation. Yet, the mechanisms linking sex hormones, pregnancy, and skin immune responses in HS remain unexplored.
By systematically comparing men, non-pregnant women, and pregnant women, in both health and HS, this study will map immune cell populations in the skin and determine how sex hormones; testosterone, estrogens, and progesterone; shape cutaneous immunity at steady state and during inflammation.
- Conditions
- Skin Immunity
- Being tested
- Blood sample, skin microbiota and biopsy
- Keywords
- Pregnancy, Maternal Immunity, Skin, Hormones, Single Cell, Spatial-Omics
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blood sample, skin microbiota and biopsyProcedure or surgery
Blood sample (maximum 40mL) Skin microbiota (collection of cells from the skin surface using a swab (non-invasive) Skin biopsy, in hormone-dependent areas and/or in a non-hormone-dependent areas
| Study group | Role | What they receive |
|---|---|---|
| Healthy - Pregnant women | Adult woman, not affected by Hidradenitis Suppurativa, pregnant in her third trimester Receives: Procedure: Blood sample, skin microbiota and biopsy | |
| Healthy - Non-pregnant women | Adult woman, not affected by Hidradenitis Suppurativa Receives: Procedure: Blood sample, skin microbiota and biopsy | |
| Healthy - Men | Adult men, not affected by Hidradenitis Suppurativa Receives: Procedure: Blood sample, skin microbiota and biopsy | |
| Hidradenitis suppurativa - Pregnant women | Adult woman, affected by Hidradenitis Suppurativa, pregnant in her third trimester Receives: Procedure: Blood sample, skin microbiota and biopsy | |
| Hidradenitis suppurativa - Non-pregnant women | Adult woman, affected by Hidradenitis Suppurativa Receives: Procedure: Blood sample, skin microbiota and biopsy | |
| Hidradenitis suppurativa - Men | Adult men, affected by Hidradenitis Suppurativa Receives: Procedure: Blood sample, skin microbiota and biopsy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Evaluate the impact of sex hormones and pregnancy on skin immunity by comparing immune cell populations in different populations (pregnant women, non-pregnant women, and men) with or without hidradenitis suppurativa.
Percentage of key skin immune cells (ILC2, dendritic cells, Langerhans cells), according to sex, pregnancy, and pathological context (healthy vs HS).
Measured: 4 years
Secondary outcomes (3)
Defining the spatial organisation of skin cells in order to assess how pregnancy remodels cutaneous immune responses in health and HS inflammation.
Immune cell mapping in healthy vs. inflamed skin biopsies across hormonal states (e.g. pregnancy).
Measured: 4 years
Exploring how sex hormones, which are massively increased during pregnancy, and circulating immune profiling impact skin function and immunity.
Measurement of sex hormones and composition of PBMCs (Peripheral Blood Mononuclear Cells) in the blood of pregnant women and in controls (men and non-pregnant women).
Measured: 4 years
Revealing the influence of the skin microbiota on the host immune system adapting to pregnancy in healthy and HS conditions.
Skin microbial metatranscriptomic profiling at the latest stage of pregnancy and in controls (men and non-pregnant women) in healthy and HS conditions.
Measured: 4 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Dec 2025
- Study startJan 2026 (estimated)
- Primary completionJan 2030 (estimated)
- Study completionMar 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Skin ImmunityStudies of the same condition, open and under way.
- More trials run by Institut PasteurThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 240 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Institut Pasteur
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Bénédicte OULES, MD-PhD, Principal investigator, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07291193
- Sponsor's protocol ID
- 2024-072
- Other IDs
- 2025-A00923-46
- Acronym
- SIAP
- Status last verified
- Nov 2025
- First submitted
- 5 Dec 2025
- Last updated
- 9 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Sex Hormones on Human Skin Immunity in Health and Hidradenitis Suppurativa
- ClinicalTrials.gov ID
- NCT07291193
- Acronym / sponsor ID
- SIAP / 2024-072
- Conditions
- Skin Immunity
- Keywords
- Pregnancy, Maternal Immunity, Skin, Hormones, Single Cell, Spatial-Omics
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 240 participants (estimated)
- Lead sponsor
- Institut PasteurIndustry (pharma, biotech, devices)
- Study start
- Jan 2026 (estimated)
- Primary completion
- Jan 2030 (estimated)
- Study completion
- Mar 2031 (estimated)
- First posted
- 18 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Sex hormones are major regulators of skin immunity. Pregnancy represents a unique physiological state of profound hormonal remodeling. In late pregnancy, maternal levels of estrogens, progesterone, and other hormones increase dramatically, offering an unparalleled model to study the impact of sex hormones on skin immunity. Hidradenitis suppurativa (HS) provides a clinically relevant model to examine how sex hormones modulate skin inflammation.
Detailed description
Sex hormones are major regulators of skin immunity. Recent work from Belkaid's laboratory in mice demonstrated that testosterone negatively regulated skin innate lymphoid cells (ILC2), leading to a reduction in dendritic cell accumulation and decreased activation in males, along with reduced tissue immunity. These findings highlight that sex-related differences in skin immunity emerge primarily after sexual maturation, driven by fluctuating hormone levels. However, whether these mechanisms are conserved in humans remains unknown.
Pregnancy represents a unique physiological state of profound hormonal remodeling. In late pregnancy, maternal levels of estrogens, progesterone, and other hormones increase dramatically, offering an unparalleled model to study the impact of sex hormones on skin immunity. Understanding maternal skin immunity is of particular importance, as the maternal immune system must balance tolerance to the fetus with protection against pathogens. Perturbation in this balance can have lasting effects on both maternal and child health. Faced with the dramatic increase in inflammatory and autoimmune disorders affecting children globally, understanding maternal immunity is of fundamental importance.
Hidradenitis suppurativa (HS) provides a clinically relevant disease model to examine how sex hormones modulate skin inflammation. HS is a chronic inflammatory skin disease with strong sex dimorphism: it affects predominantly women (70%) in Europe but is often more severe in men. In women, HS severity varies with the menstrual cycle and is frequently altered during pregnancy, suggesting a hormonal component in disease modulation. Yet, the mechanisms linking sex hormones, pregnancy, and skin immune responses in HS remain unexplored.
By systematically comparing men, non-pregnant women, and pregnant women, in both health and HS, this study will map immune cell populations in the skin and determine how sex hormones; testosterone, estrogens, and progesterone; shape cutaneous immunity at steady state and during inflammation.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 6
| Arm | Type | Receives |
|---|---|---|
| Healthy - Pregnant women | – | Procedure: Blood sample, skin microbiota and biopsyAdult woman, not affected by Hidradenitis Suppurativa, pregnant in her third trimester |
| Healthy - Non-pregnant women | – | Procedure: Blood sample, skin microbiota and biopsyAdult woman, not affected by Hidradenitis Suppurativa |
| Healthy - Men | – | Procedure: Blood sample, skin microbiota and biopsyAdult men, not affected by Hidradenitis Suppurativa |
| Hidradenitis suppurativa - Pregnant women | – | Procedure: Blood sample, skin microbiota and biopsyAdult woman, affected by Hidradenitis Suppurativa, pregnant in her third trimester |
| Hidradenitis suppurativa - Non-pregnant women | – | Procedure: Blood sample, skin microbiota and biopsyAdult woman, affected by Hidradenitis Suppurativa |
| Hidradenitis suppurativa - Men | – | Procedure: Blood sample, skin microbiota and biopsyAdult men, affected by Hidradenitis Suppurativa |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- As part of this study, adults (pregnant women, non-pregnant women, and men), healthy (not affected by HS) and affected by HS, will be recruited.
Key inclusion criteria (8 listed)
- Common criteria :
- Subject>18 years and <45 years,
- Written informed consent of the subject,
- Subject affiliated to the Assurance Maladie (French Health System) except Aide Médicale d'Etat (French State Medical Aid),
- Subject agrees that genomic analyses may be carried out on the samples
Key exclusion criteria (9 listed)
- Common criteria :
- Subject immunocompromised,
- Subject under legal protection (guardianship or curatorship),
- Subject is unable to provide informed consent and to comply with the study requirements due to geographical, social, or psychiatric reasons,
- Subject in other research whose procedures may influence the immune system,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Blood sample, skin microbiota and biopsyBlood sample (maximum 40mL) Skin microbiota (collection of cells from the skin surface using a swab (non-invasive) Skin biopsy, in hormone-dependent areas and/or in a non-hormone-dependent areas | Procedure or surgery | Healthy - Men, Healthy - Non-pregnant women, Healthy - Pregnant women, Hidradenitis suppurativa - Men, Hidradenitis suppurativa - Non-pregnant women, Hidradenitis suppurativa - Pregnant women |
Primary outcome
Evaluate the impact of sex hormones and pregnancy on skin immunity by comparing immune cell populations in different populations (pregnant women, non-pregnant women, and men) with or without hidradenitis suppurativa.
Time frame: 4 years
Percentage of key skin immune cells (ILC2, dendritic cells, Langerhans cells), according to sex, pregnancy, and pathological context (healthy vs HS).
3 secondary outcomes
Defining the spatial organisation of skin cells in order to assess how pregnancy remodels cutaneous immune responses in health and HS inflammation.
Time frame: 4 years
Exploring how sex hormones, which are massively increased during pregnancy, and circulating immune profiling impact skin function and immunity.
Time frame: 4 years
Revealing the influence of the skin microbiota on the host immune system adapting to pregnancy in healthy and HS conditions.
Time frame: 4 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jan 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Bénédicte OULES, MD-PhD principal investigator
Assistance Publique - Hôpitaux de Paris
Questions about this trial
What is this clinical trial studying?
An observational study of Skin Immunity, run by Institut Pasteur.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 9 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Clarisse GANIER, PhD (0145688767 ext. +33, clarisse.ganier@pasteur.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Evaluate the impact of sex hormones and pregnancy on skin immunity by comparing immune cell populations in different populations (pregnant women, non-pregnant women, and men) with or without hidradenitis suppurativa. (time frame: 4 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jan 2026.