Cause of Unexplained Anaphylaxis
|First Received Date ICMJE||July 19, 2008|
|Last Updated Date||February 19, 2014|
|Start Date ICMJE||July 2008|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE||Not Provided|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Change History||Complete list of historical versions of study NCT00719719 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Cause of Unexplained Anaphylaxis|
|Official Title ICMJE||Studies in the Pathogenesis of Idiopathic Anaphylaxis|
This study will explore the possible cause of unexplained, or idiopathic, anaphylaxis. Anaphylaxis is a rapid, life-threatening, severe reaction that occurs suddenly after contact with an allergy-causing substance, usually a particular food, drug or stinging insect. The allergen triggers mast cells to release several substances, including histamine. Histamine is responsible for many of the symptoms that may occur, such as flushing, hives, swelling of the palms and soles or tongue and vocal cords, nasal congestion, itching and tearing of the eyes, shortness of breath and wheezing, stomach pain, vomiting, low blood pressure, loss of consciousness, shock, and, rarely, death. Severe episodes of anaphylaxis are treated with epinephrine (adrenaline), followed by oral antihistamines and steroids. In more than half of cases of anaphylaxis, a clear cause is not identified. These cases are called idiopathic anaphylaxis. There is no cure or long-term preventive therapy for patients with recurrent episodes of idiopathic anaphylaxis.
People between 18 and 55 years of age who have idiopathic anaphylaxis episodes at least 6 times a year (with at least one episode every 3 months) may be eligible for this study.
Participants are evaluated at the NIH Clinical Center with the following tests and procedures:
Anaphylaxis is a severe life-threatening systemic hypersensitivity reaction resulting from the release of mediators from mast cells and basophils, and is characterized by the presence of cutaneous, respiratory, cardiovascular, or gastrointestinal signs and symptoms. Although the most common causes of anaphylaxis are reactions to foods, pharmaceutical agents, and stinging insects, a causative factor is not identified in up to 50% of individuals with recurrent anaphylaxis. These individuals are thus said to have idiopathic anaphylaxis (IA). The mechanistic cause of IA remains uncertain, although elevated levels of urinary histamine, plasma histamine, and serum tryptase are consistent with mast cell activation.
This protocol will focus on the pathogenesis of IA. Subjects 16-70 years old with episodes of unexplained anaphylaxis will be evaluated in order to correlate both clinical and laboratory features that are typical of idiopathic anaphylaxis to identify genetic and molecular pathways that may predispose to these events and to determine signaling abnormalities in mast cells. We plan to enroll up to 100 subjects in this study. We anticipate that our findings will be a first step toward the development of novel targeted therapies.
|Study Type ICMJE||Observational|
|Study Design ICMJE||Time Perspective: Prospective|
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Not Provided|
|Study Population||Not Provided|
|Intervention ICMJE||Not Provided|
|Study Group/Cohort (s)||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Recruiting|
|Estimated Enrollment ICMJE||100|
|Completion Date||Not Provided|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Subject must be at least 13 years of age and no older than 70 years of age.
Diagnosis of anaphylaxis occuring in the absence of an identitiable provoking agent of stimulus (Idiopathic Anaphylaxis [IA]) by a referral physician. Patient may carry both the diagnosis of 1A and the diagnosisi of anaphylaxis provoked by an identified stimulus.
History of anaphylaxis with a minimum of 3 episodes in the past year.
One doctor's office or ER visit of hospitalization on for anaphylaxis without an established etiology with involvement of the skin and/or mucosal tissue (e.g., flushing, itching, hives, angioedema, tongue swelling) and at least on the the following:
Letter of referral from prospective study participant's referring physician, with copies of available medical evaluation and laboratory studies
Able and willing to consider a bone marrow biopsy and aspirate
Presence of conditions which in the judgment of the investigator or the referring physician may put the subject at undue risk for travel (including frequent episodes of IA not preventable by pre-medication, acute infection, severe thrombocytopenia [minimum platelet count of 30,000], or significant cardiovascular disease)
Any medical condition that in the view of the principal investigator would make the subject unsuitable for enrollment in this study (such as advanced renal disease).
Inability to provide informed consent
|Ages||16 Years to 70 Years|
|Accepts Healthy Volunteers||No|
|Location Countries ICMJE||United States|
|NCT Number ICMJE||NCT00719719|
|Other Study ID Numbers ICMJE||080184, 08-I-0184|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Institute of Allergy and Infectious Diseases (NIAID)|
|Collaborators ICMJE||Not Provided|
|Information Provided By||National Institutes of Health Clinical Center (CC)|
|Verification Date||February 2014|
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