Phenotypic and Functional Profile of Peripheral Blood Lymphomonocytes in Seborrheic Dermatitis.

NCT07297446 | Completed

• 1 other identifier: RS 170/ISG/24
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The protocol describes a prospective, monocentric pilot study conducted at the Istituto Dermatologico San Gallicano (IFO-ISG) aimed at investigating the phenotypic and functional profile of peripheral-blood lymphomonocytes in individuals with seborrheic dermatitis (SD) compared with non-affected controls. A secondary objective is to explore dietary habits in subjects with SD. Seborrheic dermatitis is a chronic-relapsing inflammatory skin disease, common in infancy, puberty, and adulthood (40-60 years). Its multifactorial etiology involves: Sebaceous gland hyperactivity and altered lipid composition promoting Malassezia proliferation; Metabolic activation of sebaceous glands by Malassezia, which generates irritating fatty acids; Immune dysregulation, influencing keratinocyte activation and differentiation; Barrier disruption, clinically resulting in erythema, scaling, and pruritus. Previous research on immune cells in barrier tissues (gut, lung, skin) suggests that environmental factors-particularly dietary fatty acids and salt intake-modulate the functional polarization of Th17 vs. Treg cells, with implications for autoimmunity. Tissue-resident memory T cells (TRM), abundant in barrier organs, display site-specific homing markers such as CCR4, CCR10, CXCR4, GATA6, and BCL6. In contrast, circulating TEM and TEMRA subsets share common profiles across tissues. Protocollo\_Profilo fenotipico e… In skin, Th17 cells exhibit variable transcriptional states that may reflect tissue-dependent functional states rather than fixed subtypes. Studies in SD have mainly focused on cutaneous immune responses, highlighting roles for Tγδ cells, cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17, TNF-α), and β-defensins, linked to dendritic-cell maturation driven by sebaceous lipids and activation of the NLRP3 inflammasome. Malassezia can also induce IL-1β release from dendritic cells in vitro. However, little is known about how SD affects circulating immune cells or how dietary patterns influence systemic immune responses in this disease. Study population The study will include 15 SD patients and 15 non-affected (NA) controls, aged 45-75 years, of both sexes. SD patients must have mild-to-moderate facial involvement and must have stopped topical or systemic treatments for at least two weeks. Exclusion criteria include other skin diseases, neurodegenerative disorders, immunosuppression, ongoing treatments, or HIV positivity. Controls are selected from IFO staff, relatives, and individuals undergoing routine dermatologic examinations. Methods After overnight fasting, participants undergo venous blood sampling (7 mL). Plasma is separated and stored at -80°C for secretory and lipidomic profiling. Lymphomonocytes are isolated using Ficoll-Hypaque gradients and analyzed by flow cytometry to characterize immunological phenotypes. Each participant completes a dietary questionnaire at enrollment. Collected data include demographics, clinical history, dietary information, laboratory findings, and SD-specific clinical data (for the patient group). Statistical plan As a pilot study, data will be summarized with descriptive statistics only; no formal comparisons will be performed. Findings will generate hypotheses for future research. Recruitment is planned over 18 months, with a total study duration of 24 months. Ethical and administrative aspects The study adheres to Good Clinical Practice, the Declaration of Helsinki, and EU/national regulations. Ethical approval is required before initiation. Participants must provide written informed consent for both study participation and data processing. Data will be handled in compliance with GDPR, using pseudonymization, secure storage, and restricted access. Authorized monitors and regulatory authorities may inspect source documents. Biologic samples will be stored until completion of analyses. Results will be published in aggregated, non-identifiable form in scientific journals and conferences.

Conditions

Seborrheic Dermatitis; Dietary Habits

Keywords

phenotypic and functional profile; peripheral-blood lymphomonocytes; seborrheic dermatitis (SD)

Outcome Measures

Primary Outcomes (1)

• Phenotypic and Functional Profile of Peripheral Blood Lymphomonocytes

  Evaluation of the immunological profile of Peripheral Blood Mononuclear Cells (PBMCs) in patients with Seborrheic Dermatitis compared to healthy controls. The analysis includes: Phenotypic Characterization (Flow Cytometry): Expression of cell surface markers to identify Regulatory T cells (CD45, CD4, CD25, CD127, FoxP3), general immune subsets (CD3, CD4, CD8, CD14, CD16, CD19, CD45, CD56), and activated T cells (CD8, HLA-DR, CD38, CD3, CD4, CD45RA, CD197). Functional/Secretory Profile (Multiplex/ELISA): Measurement of plasma concentrations of the following cytokines: IL-4, IL-5, IL-8, IL-12, IL-13, IL-18, IL-31, TNF-a, IFN-a, IFN-g, GRO-a, IL-6, IL1a/b, IL-20, IL-23, IL-17A/F, IL-22, GM-CSF, and TSLP.

  Baseline (Day 1)

Secondary Outcomes (1)

• Assessment of Dietary Habits

  Baseline (Day 1)

Study Arms (2)

Seborrheic Dermatitis (DS)

Participants aged 45-75 years with mild-to-moderate facial seborrheic dermatitis. Additional sebaceous areas may be affected. Blood samples are collected for plasma analysis (secretory and lipidomic profiling) and for lymphomonocyte isolation and flow cytometric phenotyping. Participants also complete a dietary habits questionnaire.

Non-Affected Controls (NA)

Healthy volunteers aged 45-75 years with no seborrheic dermatitis or other relevant dermatologic diseases. Controls undergo the same laboratory and questionnaire procedures as the DS group.

Eligibility Criteria

• Age: 45 Years - 75 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of people affected by SD (Seborrheic Dermatitis), both female and male, aged between 45 and 75 years, and healthy subjects selected from personnel undergoing routine examinations by the IFO Occupational Health Unit (Medicina del Lavoro IFO) and among members, friends, and relatives of the personnel of the Cutaneous Physiopathology Unit (UOC Fisiopatologia Cutanea).

You may qualify if:

• Patients affected by Facial Seborrheic Dermatitis (SD) of mild to moderate severity; other sebaceous areas of the body may also be affected.
• Both sexes. Age 45-75 years. Treatments for SD, topical and/or systemic, suspended for at least two (2) weeks.
• Willingness to comply with the appointments/procedures required by the study. Signature of the informed consent.

You may not qualify if:

• Diagnosed neurodegenerative diseases. Ongoing pharmacological treatment, topical or systemic, for Seborrheic Dermatitis (SD).
• Immunosuppression. HIV seropositivity.

Sponsors & Collaborators

• San Gallicano Dermatological Institute IRCCS: lead

Study Sites (1)

San Gallicano Dermatological Institute IRCCS

Roma, Italy, 00144, Italy

Location

MeSH Terms

Conditions

Dermatitis, Seborrheic; Feeding Behavior

Condition Hierarchy (Ancestors)

Dermatitis; Skin Diseases; Skin and Connective Tissue Diseases; Sebaceous Gland Diseases; Skin Diseases, Eczematous; Skin Diseases, Papulosquamous; Behavior, Animal; Behavior

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Day
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 9, 2025
• First Posted: December 22, 2025
• Study Start: June 19, 2024
• Primary Completion: February 14, 2025
• Study Completion: June 10, 2025
• Last Updated: December 22, 2025

Record last verified: 2025-12

Locations

IT (1)