This study aims to uncover the specific immunopathology, microbiome and pathophysiology of acne vulgaris in people living in a tropical climate such as Singapore. This is a largely unexplored population in terms of acne pathogenesis, and will lead to population-specific interventions for the management of acne vulgaris.

The main objective of this translational study in healthy participants and in mild, moderate and severe acne participants is to deepen the current understanding of acne aetiology. A multi-omics approach will be leveraged to analyse the interactions between the local skin microbiota and host factors found in different stages of acne vulgaris and generate hypotheses on how these may contribute to different disease manifestations.

General objectives:

I. Deepen the current understanding of acne aetiology II. Identify key biological markers of disease severity and specific immune pathways III. Describe bacterial components associated with disease severity and inflammatory immune response IV. Determine antigens of the natural immune response against C. acnes

Data collected from participants includes:

• Demographic Data [age, sex, ethnicity, body mass index (BMI)]
• Skin type (using the Fitzpatrick skin classification scale)

Samples collected from participants:

• Pore Strip Application (comedo extraction)
• Facial swabbing
• Facial tape stripping
• Blood Samples
• Facial biopsies (optional)

INCLUSION CRITERIA:

AGE I01: Aged 18 to 25 years on the day of inclusion.

TYPE OF PARTICIPANT AND DISEASE CHARACTERISTICS

I02: Participants with a formal diagnosis of either:

• Mild facial acne vulgaris defined as Investigator's Global Assessment (IGA) of 2, or
• Moderate facial acne vulgaris defined as IGA score of 3, or
• Severe facial acne vulgaris defined as IGA score of 4, or
• Healthy volunteers without acne defined as IGA score of 0.

INFORMED CONSENT I03: Informed consent form has been signed and dated by participant capable of providing informed consent.

Note: For minor participants, informed consent form must also be signed and dated by the parent(s) or another legally acceptable representative(s).

OTHER INCLUSIONS I04: Participant or participant and parent(s)/legally acceptable representative(s) are able to attend all scheduled visits and to comply with all study procedures.

EXCLUSION CRITERIA

Participants are not eligible for the study if any of the following criteria are met:

MEDICAL CONDITIONS E01: Thrombocytopenia, presence of bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating blood sampling, currently or previously suffering from any immune disorder.

E02: Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.

E03: Active nodulocystic acne, acne conglobata, acne fulminans, secondary acne (eg, chloracne, drug-induced acne) or other forms of acne (eg, acne mechanica).

E04: Skin pathology or condition that, in the investigator's opinion, could interfere with the evaluation of the study intervention or requires use of interfering topical, systemic, or surgical therapy.

E05: Excessive facial hair, facial tattoos, facial skin disorders, skin reactions that may interfere with the study assessments in the investigator's opinion (including - but not limited to - actinic keratosis, eczema, psoriasis, seborrheic dermatitis, rosacea, acute or recent sunburn) or skin infection.

E06: Alcohol, prescription drug, or substance abuse that, in the opinion of the investigator, might interfere with the study conduct or completion.

E07: Self-reported or documented seropositivity for human immunodeficiency virus (HIV), hepatitis B virus, or hepatitis C virus.

E08: Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of samplings. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.

PRIOR/CONCOMITANT THERAPY:

E09: Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within 6 months prior to the study sample collection; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks) within 3 months from study sample collection.

E10: Start or switch of hormonal contraceptive use within 12 weeks prior to the study visit.

E11: Previous use of oral isotretinoin. E12: Use of any acne-affecting treatment without an appropriate washout period (antibacterial/antifungal/antiseptic medications or topicals). Participants receiving prohibited medications/therapies at Screening Visit will have to observe a washout period of 2 to 24 weeks before enrolment to preserve eligibility in the study.

E13: Previous vaccination against C. acnes with an investigational vaccine E14: Receipt of immune globulins, blood or blood-derived products in the past 3 months E15: Pregnant or lactating women

PRIOR/CONCURRENT CLINICAL STUDY EXPERIENCE E16: Participation at the time of study enrolment or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.

OTHER EXCLUSIONS:

E17: Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.

E18 Identified as an Investigator or employee of the Investigator or study centre with direct involvement in the proposed study, or identified as an immediate family member (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study.

Participants aged 18 to 25 years, with or without mild, moderate, or severe acne will be recruited from the Singapore population.

Collaborators still undecided