OJO-miR: microRNA Expression in Allergic Conjunctivitis.

Instituto de Oftalmología Fundación Conde de Valenciana

Status: Active, not recruiting

Conditions: Conjunctivitis, Allergic

Study type: Observational

Funder types: Other

Identifiers

NCT07385495

CEI-2025/09/05

Research Committee (Other Identifier)

Biosecurity Committee (Other Identifier)

Details and patient eligibility

About

Allergic conjunctivitis (AC) causes inflammation of the conjunctiva in response to environmental allergens, affecting a significant percentage of the world population and reducing quality of life. The pathophysiology is poorly understood, lacking effective treatments. MicroRNAs have potential for diagnosing and characterizing inflammatory diseases. This study aims to compare the expression profiles of inflammation-regulating microRNAs (miR-19, miR-23, miR-125b, miR-146a, and miR-155) in serum and tear samples from subjects with AC and healthy subjects to identify biomarkers and therapeutic targets.

Full description

Allergic conjunctivitis (AC) is an inflammatory disorder of the conjunctiva triggered by exposure to environmental allergens. This ocular condition affects a significant proportion of the global population, leading to a reduction in quality of life and, in some cases, visual impairment. The pathophysiology of AC remains poorly understood, and effective targeted therapies are limited. MicroRNAs have emerged as promising tools for the diagnosis and characterization of inflammatory diseases such as asthma and rhinitis; however, studies evaluating microRNA involvement in allergic conjunctivitis are scarce. Therefore, identifying microRNAs that are differentially regulated in AC is essential to better understand disease pathogenesis and to explore potential biomarkers and therapeutic targets.

This study aims to determine whether differences exist in the expression profiles of inflammation-regulatory microRNAs between subjects with allergic conjunctivitis and healthy controls. The working hypothesis is that subjects with allergic conjunctivitis exhibit differential expression of inflammation-related microRNAs compared with healthy individuals.

An observational cross-sectional study will be conducted including subjects aged 5 to 30 years with a clinical diagnosis of allergic conjunctivitis, as well as age-matched healthy controls. Tear samples and peripheral blood samples for serum isolation will be collected from all participants. Total RNA will be extracted from both sample types, and the expression of miR-19, miR-23, miR-125b, miR-146a, and miR-155 will be quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Relative expression levels (fold change) will be calculated in the allergic conjunctivitis group and compared with those observed in healthy controls to identify microRNAs specifically associated with the disease. Receiver operating characteristic (ROC) curve analysis will be performed to evaluate the potential of the studied microRNAs as diagnostic biomarkers.

Enrollment: 40 estimated patients

Sex: All

Ages: 5 to 30 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria

• Subjects with Allergic Conjunctivitis:
• Age between 5 and 30 years.
• Clinical diagnosis of allergic conjunctivitis.
• Presence of active ocular symptoms at the time of sample collection.
• Positive skin prick test.
• Written informed consent signed by the participant or parent/legal guardian, -with assent when applicable.

Healthy Controls:

• Age between 5 and 30 years.
• Clinically healthy subjects with a normal ocular surface.
• No evidence of active ocular disease.
• Written informed consent signed by the participant or parent/legal guardian, with assent when applicable.

Exclusion Criteria

• Subjects with Allergic Conjunctivitis:
• History of infectious disease within 2 months prior to sample collection.
• Presence of active systemic allergic diseases (e.g., asthma, active dermatitis).
• Chronic degenerative or autoimmune diseases.
• Use of topical immunosuppressive treatment within 2 months prior to sample collection.
• Use of systemic immunosuppressive therapy.

Healthy Controls:

-History of infectious disease within 2 months prior to sample collection.

Trial design

40 participants in 2 patient groups

Subjects with Allergic Conjunctivitis

Description:

Subjects aged 5 to 30 years with a confirmed clinical diagnosis of allergic conjunctivitis (Seasonal, Perennial, or Vernal Keratoconjunctivitis). Participants must present active symptomatology and positive skin prick tests corresponding to the allergic condition.

Healthy Controls

Description:

Clinically healthy subjects aged 5 to 30 years with a normal ocular surface evaluation. Participants must have no personal history of allergic diseases (ocular or systemic), no active ocular infection, and no chronic-degenerative or autoimmune diseases.