An observational study in Conjunctivitis, Allergic, sponsored by Instituto de Oftalmología Fundación Conde de Valenciana. Not yet recruiting at 1 site in Mexico. Open to participants aged 5 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-17.
Sponsored by Instituto de Oftalmología Fundación Conde de Valenciana · Observational
This study aims to evaluate the effector function and expression of TIGIT and PD-1 on Tregs, as well as the Th2/Treg ratio, in patients with allergic conjunctivitis with and without desensitization therapy, compared to healthy controls.
Peripheral blood and tear samples will be collected once at enrollment. Treg and Th2 populations will be immunophenotyped, TIGIT and PD-1 expression assessed, and functional assays performed. Cytokine and antibody (IgE, IgG4) concentrations will be measured in serum and tears.
Results will be analyzed using descriptive statistics, Shapiro-Wilk test for distribution, t-tests or ANOVA for group comparisons, and correlation analyses for associations, with p\<0.05 considered significant. This study seeks to identify immunological markers associated with disease severity and treatment response, potentially informing future therapeutic strategies.
Allergic conjunctivitis is a prevalent ocular condition affecting approximately 10-20% of the global population, with 40-60% of allergic individuals exhibiting ocular symptoms. It is characterized by redness, itching, burning, and tearing, which result from excessive activation of immune response cells. Severe forms can significantly impact vision and quality of life, particularly in children, adolescents, and young adults. The disease is mediated by hypersensitivity reactions: Th2 lymphocytes release cytokines (IL-4, IL-5, IL-13) that stimulate IgE production by B lymphocytes. IgE binds to mast cells and induces the release of pro-inflammatory mediators upon allergen recognition. Regulatory T cells (Tregs) play a critical role in maintaining immune homeostasis by suppressing the activation and proliferation of effector T cell subsets, including Th1, Th2, Th9, and Th17, via cell-surface molecules such as TIGIT, LAP-TGF-β, and PD-1. Additionally, Tregs produce IL-10, which suppresses IgE production and induces IgG4 secretion by B cells. Allergen-specific immunotherapy (desensitization) has been employed to reduce symptoms and prevent recurrence in allergic diseases.
Rationale:
Allergic conjunctivitis is a public health concern that affects the quality of life of a substantial portion of the Mexican population. Immunological imbalances between effector T cells and Tregs have been reported. Understanding the balance of these subpopulations and the role of TIGIT and PD-1 molecules in Treg functional status is critical to elucidating disease mechanisms. Moreover, it is important to determine whether desensitization therapy induces changes in the Th2/Treg ratio and modulates TIGIT and PD-1 expression, which could serve as biomarkers of treatment response or therapeutic targets.
Hypothesis:
The effector function and expression of TIGIT and PD-1 on Tregs are decreased in patients with allergic conjunctivitis and are enhanced following desensitization therapy.
Objectives:
The primary objective is to evaluate the effector function and expression of TIGIT and PD-1 on Tregs and the Th2/Treg ratio in patients with allergic conjunctivitis with and without desensitization therapy, compared to healthy controls. Secondary objectives include assessing correlations between immunological parameters and clinical severity of ocular symptoms and response to treatment.
Study Design and Methods:
This observational, cross-sectional, case-control study will include patients with allergic conjunctivitis, with or without desensitization therapy, and healthy control subjects. Peripheral blood and tear samples will be collected once at enrollment. Peripheral blood mononuclear cells will undergo immunophenotyping to quantify Treg and Th2 populations and assess TIGIT and PD-1 expression. Tregs will be isolated for functional assays. Cytokine concentrations associated with Th2 and Treg cells, as well as IgE and IgG4 levels, will be measured in serum and tears.
Statistical Analysis:
Descriptive statistics will summarize participant characteristics and study outcomes. The Shapiro-Wilk test will assess data distribution. Comparisons between two groups will use t-tests (parametric or non-parametric), and comparisons among more than two groups will use ANOVA (parametric or non-parametric). Correlation analyses will evaluate associations between immunological parameters and clinical outcomes. A p-value \<0.05 will be considered statistically significant.
210 studies on the registry are indexed under Conjunctivitis, Allergic; 18 are open to participants now.
This study's planned enrollment of 60 is below the median of 107 across 28 observational studies indexed under Conjunctivitis, Allergic.
Browse Conjunctivitis, Allergic studies →Instituto de Oftalmología Fundación Conde de Valenciana is the lead sponsor of 45 studies on the registry; 10 are open to participants now.
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The study subjects are patients recruited from the outpatient clinic of "Clinical Immunology" at Instituto de Oftalmologia Conde de Valenciana. All patients are evaluated by specialists in ophthalmology and allergy.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The study subjects will be patients with a confirmed diagnosis of allergic conjunctivitis, active symptoms, and positive skin tests, who do not present any other type of systemic or local disease or inflammatory process and who are receiving allergen-specific immunotherapy (AIT).
The study subjects will be patients with a confirmed diagnosis of allergic conjunctivitis, active symptoms, and positive skin tests, who do not present any other type of systemic or local disease or inflammatory process, and who are not receiving immunotherapy treatment.
The control subjects will be clinically healthy individuals, with a normal ocular surface and no evidence of active ocular disease or local or systemic inflammatory or infectious processes.
To evaluate the effector function and the expression of TIGIT and PD-1 molecules on regulatory T cells, as well as the Th2/Treg, in patients with allergic conjunctivitis with and without allergen-specific immunotherapy, and in healthy control subjects.
Patients with allergic conjunctivitis, both with and without desensitization treatment, as well as healthy subjects as a control group, will be included in the study. Peripheral blood and tear samples will be collected from all participants. Peripheral blood samples will be used for immunophenotyping of Treg and Th2 lymphocytes and for assessing the expression levels of the effector molecules TIGIT and PD-1.
Time frame: At baseline (single assessment at enrollment in all study and control groups)
Proportion of Treg and Th2 lymphocytes and Th2/Treg ratio in peripheral blood
Peripheral blood mononuclear cells will be immunophenotyped to quantify Treg and Th2 populations and calculate the Th2/Treg ratio.
Time frame: At baseline (single assessment at enrollment in all study and control groups)
Cytokine profile associated with Treg and Th2 lymphocytes in serum and tears
Concentrations of cytokines related to Treg (e.g., IL-10) and Th2 (e.g., IL-4, IL-5, IL-13) will be measured in serum and tear samples.
Time frame: At baseline (single assessment at enrollment in all study and control groups)
Effector function of Treg lymphocytes assessed by TIGIT and PD-1 expression and functional assays.
Treg cells will be analyzed for expression of effector molecules TIGIT and PD-1, and functional assays will be performed to assess suppressive capacity.
Time frame: At baseline (single assessment at enrollment in all study and control groups)
Concentration of IgE and IgG4 antibodies in serum and tears
Serum and tear samples will be analyzed to determine levels of IgE and IgG4 antibodies.
Time frame: At baseline (single assessment at enrollment in all study and control groups)
Correlation of immunological parameters with ocular symptom severity and treatment response
Associations between immunological markers (Treg/Th2 ratio, cytokine levels, IgE/IgG4 concentrations, TIGIT/PD-1 expression) and clinical outcomes will be evaluated.
Time frame: At enrollment (clinical evaluation performed once in all study and control groups)
Plan to share: No
Start is estimated for Jan 2026; primary completion for Sep 2026, 8 months later.
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This study is not yet recruiting, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.
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Instituto de Oftalmología Fundación Conde de Valenciana