Advertisement

Topics

Role of T-Cells in Asthma

2014-08-27 03:59:35 | BioPortfolio

Summary

This study will examine the movement of T cells (a type of white blood cell) from the blood to the lungs in patients with asthma after exposure to an allergen, such as cat dander or pollen. Asthma is in large part due to inflammation of the bronchi (the breathing tubes of the lungs), causing heat, swelling and redness. T cells play a major role in the inflammatory reaction. A better understanding of T cell migration to the lungs after allergen exposure may lead to improved therapies for asthma.

Patients between 18 and 50 years of age with mild allergic asthma may be eligible for this study. In addition, patients and healthy normal volunteers between 18 and 65 years of age may participate in a sub-study (blood draw) of this protocol. Participants will undergo the following procedures:

Visit 1 (screening visit)

- Blood tests for blood counts and HIV

- Urine pregnancy test for women of childbearing potential.

Visit 2

- Physical examination and electrocardiogram (EKG)

- Prick skin testing - A drop of allergen extract is put on the skin and the underlying skin is scratched with a needle. A positive test resembles an insect bite and may itch.

- Intradermal skin tests - Increasing concentrations of a drop of diluted allergen are injected into the skin and the allergic response is monitored until a 5-mm swelling (1/4 inch) swelling develops.

- Methacholine challenge - The subject has repeated pulmonary function (breathing) tests after breathing methacholine, a drug that temporarily (for 5 to 10 minutes) worsens asthma symptoms.

- Physician evaluation and repeat pulmonary function test

Visit 3

- Allergen bronchoprovocation - This test will be done in patients whose physical evaluation and breathing test permit them to continue with the study. A heparin lock (needle device that stays in a vein to allow multiple blood draws without repeated sticks) is placed. The subject breathes 5 breaths of allergen through a nebulizer (device that creates a mist), followed by a breathing test. This procedure will be repeated with increasingly higher allergen doses until lung function significantly declines or for a maximum of 6 doses. Subjects are monitored for 8 hours after the last dose. Blood samples of 50 ml each (3.5 tablespoons) are collected at 1, 3, 5 and 8 hours, and a physician evaluation is done at the end of the 8 hours. Additional 50-mm blood samples are collected the following two mornings.

Visit 4

- Physician evaluation, blood test for anemia and pulmonary function test

- Serial blood draws - 50 ml of blood will be drawn, followed by salt-water nebulization and another 50-ml blood draw after 1 hour. Additional 50-ml blood samples will be drawn 7 hours later and then on the next two mornings.

Participants in the sub-study portion of this protocol will undergo the screening blood test, prick skin testing, breathing test after methacholine inhalation and a 100 ml-blood draw. These tests will be done in three sessions.

Description

In the last 10 years it has become generally accepted that asthma is an inflammatory disease of the airways. T lymphocytes play a key role in regulating this inflammatory response, through the elaboration of cytokines such as IL-4, IL-5, and IFN-gamma. IL-5 is of particular interest because it is the major eosinophil survival factor in vivo. Eosinophils are felt to be the major effector cells in asthma, causing damage to various airway structures.

The pulmonary late phase response, a worsening of airflow seen 4-8 hours after allergen inhalation, is associated with many of the inflammatory changes seen in chronic asthma. Current studies suggest that during the late phase response peripheral blood T cells traffic to the lungs and express cytokines, specifically IL-4 and IL-5.

We propose to investigate this trafficking by determining the frequencies and phenotype of cells capable of producing the above cytokines in the peripheral blood in subjects with mild allergic asthma. These studies should lead to a clearer understanding of the cells and processes that lead to T cell trafficking to the lung and may yield a tool to evaluate the proposed anti-inflammatory therapies for asthma.

Study Design

N/A

Conditions

Asthma

Location

National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda
Maryland
United States
20892

Status

Completed

Source

National Institutes of Health Clinical Center (CC)

Results (where available)

View Results

Links

Published on BioPortfolio: 2014-08-27T03:59:35-0400

Clinical Trials [1363 Associated Clinical Trials listed on BioPortfolio]

Impact of Adult Asthma

To assess the separate and interactive effects of asthma severity, subspecialty practice variation, asthma-related psychosocial variables, and other factors on asthma outcomes, including a...

Improving the Quality of Asthma Care Using the Internet

It is important for people with asthma to become involved in their asthma care and management. This study will evaluate an interactive Web site that provides tailored feedback and informat...

Asthma Inpatient Research on Education

Families of children with asthma are admitted for asthma attacks very frequently compared to adults with asthma. They are given education about asthma but studies are needed to improve thi...

Improving Asthma Communication in Minority Families

The purpose of this study is to determine if teaching children with asthma how to talk to their doctor about controlling their asthma including symptom frequency in an asthma diary and med...

Asthma Control, Quality of Life and Emotional Feelings in a Real Life Setting

This study aims to evaluate the asthma control status, asthma symptoms (severity, frequency, and limitations on activities, etc.), QOL, and use of drugs for asthma attack in adult asthma p...

PubMed Articles [998 Associated PubMed Articles listed on BioPortfolio]

Update: Asthma Yardstick: Practical recommendations for a sustained step-up in asthma therapy for poorly controlled asthma.

Perimenstrual asthma: Report of a case with therapeutic intervention of oral prednisone.

Many asthmatic women of childbearing age experience cyclical aggravation of asthmatic symptoms during the perimenstrual period, or perimenstrual asthma (PMA). PMA is considered to be a difficult-to-tr...

Treatment patterns and related clinical consequences in adults with asthma.

A stepwise therapeutic management is recommended for asthma patients by the Global Initiative for Asthma (GINA). Little is known about the recommendations applied in real world settings. This study ai...

Seasonal changes influence the improvement in asthma symptoms by exercise training in subjects with asthma.

To investigate whether patients with moderate to severe asthma who commence an exercise training program in winter or summer show differences in exercise capacity, health-related quality of life (HRQo...

Characterisation of asthma in the adolescent population.

Asthma often debuts in early life (1). During childhood, the prevalence of asthma is higher in boys, but prevalence is higher in girls after puberty (2). The goal of asthma treatment is to achieve and...

Medical and Biotech [MESH] Definitions

Asthma attacks caused, triggered, or exacerbated by OCCUPATIONAL EXPOSURE.

Asthma attacks following a period of exercise. Usually the induced attack is short-lived and regresses spontaneously. The magnitude of postexertional airway obstruction is strongly influenced by the environment in which exercise is performed (i.e. inhalation of cold air during physical exertion markedly augments the severity of the airway obstruction; conversely, warm humid air blunts or abolishes it).

Drugs that are used to treat asthma.

A beta-adrenergic agonist used in the treatment of asthma and bronchospasms.

Adrenergic beta-2 agonist used as bronchodilator for emphysema, bronchitis and asthma.

More From BioPortfolio on "Role of T-Cells in Asthma"

Advertisement
Quick Search
Advertisement
Advertisement

 

Relevant Topic

Allergies
The term allergy is used to describe a response, within the body, to a substance, which is not necessarily harmful in itself, but results in an immune response and a reaction that causes symptoms and disease in a predisposed person, which in turn can cau...


Searches Linking to this Trial