Regulatory Lymphocytes in Patients Treated With Specific Immunotherapy
Keywords
Abstract
Description
Allergy constitutes an important problem worldwide thus effective treatment is crucial for the reduction of symptoms severity, patients' activity and quality of life as well as for the reduction of direct and indirect costs of the disease. Specific allergen immunotherapy (SIT) is a potentially curative and specific method of treatment for allergic diseases, particularly for intermittent allergic rhinitis. Specific subcutaneous immunotherapy induce peripheral tolerance and suppress inflammation in tissue. In periphery, effector T cells unresponsiveness to antigens is mediated mainly by allergen specific regulatory T cells. Regulatory T cells induced peripherally comprise IL-10 producing type 1 regulatory T cells (Tr1) and regulatory T cells subset arising in vitro from CD4+CD25- and in vivo from peripheral memory T cells whereas naturally occurring Tregs (nTregs)originate in thymus and represent about 5% of the peripheral CD4 T cells and constitutively express high levels of the high-affinity IL-2 receptor (CD25hi). They coexpress Forkhead Box Protein P3 (Foxp3), glucocorticoid induced tumor necrosis factor receptor (GITR), cytotoxic T lymphocyte associated antigen (CTLA-4), and display low expression of alpha chain of the IL-7 receptor. Although clinical and immunological outcomes of SIT, that are associated with regulatory T cells functions were profoundly studied, little is known about the molecular mechanisms that are crucial for nTregs activation and function in the course of SIT. Since histamine is a key mediator in allergy that exerts its effect through 4 types of histamine receptors we decided to investigate the expression of histamine 2 receptor, that has potent immunomodulatory properties, in regulatory lymphocytes in patients treated with SIT. Furthermore, since T cell receptor activation is essential for T effector lymphocytes activation we wanted to check the expression of zeta chain associated protein (ZAP70), that constitutes a linker between TCR and lower levels of intracellular downstream signal transduction, in regulatory T cells in the course of SIT.
This is a 3-year prospective, placebo controlled, double blind trial of grass SIT. 41 patients with seasonal allergic rhinitis were randomized to receive SIT (n = 21) or placebo (n = 20) and 15 healthy were included as a control. The primary and secondary outcomes were assessed at baseline and during the treatment period - before the start of the pollen season, at the height of the pollen season and after the end of the pollen season.Results were compared between the treatment year and baseline and between the groups treated with SIT, placebo and healthy control.
Dates
| Last Verified: | 10/31/2011 |
| First Submitted: | 11/15/2011 |
| Estimated Enrollment Submitted: | 11/17/2011 |
| First Posted: | 11/20/2011 |
| Last Update Submitted: | 11/17/2011 |
| Last Update Posted: | 11/20/2011 |
| Actual Study Start Date: | 02/28/2007 |
| Estimated Primary Completion Date: | 09/30/2010 |
| Estimated Study Completion Date: | 11/30/2010 |
Condition or disease
Intervention/treatment
Drug: Specific subcutaneous immunotherapy
Other: placebo
Phase
Arm Groups
| Arm | Intervention/treatment |
|---|---|
| Placebo Comparator: placebo 20 patients with intermittent allergic rhinitis sensitized to grass pollen allergens | Other: placebo placebo administered with the same scheme and doses as specific subcutaneous immunotherapy |
| Active Comparator: Specific subcutaneous immunotherapy 21 symptomatic patients with intermittent allergic rhinitis sensitized to grass pollen allergens | Drug: Specific subcutaneous immunotherapy commercially available grass pollen allergoid (100%), concentration A (1000 TU/ml, therapeutic units/ml)concentration B (10000 TU/ml).Patients were given subcutaneous injections with initial dose of 0.1 ml (concentration A) was increased once a 7 (+7) days until the highest tolerated dose (0.6, concentration B) was reached and SIT was continued with injections once every 4 - 6 weeks up to two years. |
Eligibility Criteria
| Ages Eligible for Study | 18 Years To 18 Years |
| Sexes Eligible for Study | All |
| Accepts Healthy Volunteers | Yes |
| Criteria | Inclusion Criteria: - seasonal allergic rhinitis with or without allergic conjunctivitis - sensitization to grass pollen allergens (confirmed with skin prick tests, conjunctival provocation test, specific IgE) - symptoms of allergic rhinitis with or without conjunctivitis for at least 2 years before the study Exclusion Criteria: - sensitization to allergens, that could interfere with grass pollen - asthma - cystic fibrosis - ciliary dysmotility syndrome - bronchiectasis - smoking - tuberculosis - neoplastic disease - chronic sinusitis and nasal polyps - systemic glucocorticosteroids treatment - treatment with immunotherapy in the past |
Outcome
Primary Outcome Measures
1. numbers of regulatory T lymphocytes (nTregs) [Change from the baseline year to the 2nd year of immunotherapy.]
Secondary Outcome Measures
1. Expression of zeta chain associated protein (ZAp70) in regulatory lymphocytes (nTregs) [Change from the baseline year to the 2nd year of immunotherapy]
2. Expression of histamine H2 receptor in regulatory lymphocytes (NTregs) [Change from the baseline year to the second year of immunotherapy]
3. Rhinoconjunctivitis symptom score [Change from the baseline year to the second year of immunotherapy]
4. Nasal eosinophilia [Change from the basline year to the 2nd year of immunotherapy]
5. Concentration of nitric oxide in exhaled air [Change from the baseline year to the 2nd year of immunotherapy]
6. Consumption of rescue medications [Change from the baseline year to the second year of imunotherapy]
