An observational study in Immune System Diseases, Eosinophilia and Helminthiasis, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Recruiting at 1 site in United States. Open to participants aged 1 Year to 100 Years. Per ClinicalTrials.gov, last updated 2026-09-28.
Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Observational
This study will investigate how, why and under what conditions eosinophils (a type of white blood cell) become activated and will examine their function in immune reactions. Eosinophil counts often rise in response to allergies, asthma, and parasitic worm infections. They can also go up in uncommon autoimmune conditions and, rarely, in association with tumors. Elevated levels of these cells is called eosinophilia. Usually, eosinophilia causes no apparent symptoms, but in rare cases there may be local swelling and itching, allergic lung problems, heart disease or nerve damage caused by the release of toxic substances in these cells into body tissues.
Patients 1 to 100 years of age with eosinophil counts greater than 750/ml or an abnormal accumulation of eosinophils in the skin or body tissues may be eligible for this study. All participants will have a thorough medical history, physical examination and blood tests. Depending on the person's age and symptoms, other diagnostic tests may be done, including specialized studies of the eye, lungs, skin, bone marrow, nerves or heart. This is not a treatment study, and no experimental treatments will be offered. Patients who require treatment will receive standard medical care.
Certain other procedures may be requested solely for research purposes. All participants will be asked to donate extra blood for laboratory studies investigating how immune cells and other immune substances in the blood act to stimulate a rise in eosinophils. In addition, some participants may undergo one or more of the following:
Study Description: This study is designed to collect data and clinical samples from participants with elevated eosinophil counts in the peripheral blood or tissues or their relatives to enhance our understanding of the mechanisms driving eosinophilia and eosinophil activation in patients with a wide range of eosinophilic disorders with the ultimate goal of improving diagnostics and identifying novel treatment modalities for these patients. Eosinophilic participants will undergo an extensive clinical evaluation at baseline and at least yearly thereafter focused on the identification of the cause of eosinophilia and the presence of end organ manifestations. Blood, bone marrow, tissue, and/or body fluids will be collected for research purposes at initial and follow-up visits to address broader questions relating to the varied etiologies of eosinophilia, biomarkers of disease activity and eosinophil activation, and the functional role of eosinophils in homeostasis and disease pathogenesis. While this protocol is not primarily designed to study treatment of eosinophilic patients, the clinical and immunological responses to therapy will be monitored. This protocol will also allow clinical and laboratory evaluation of family members of subjects with eosinophilia to help identify genetic causes of eosinophilia and to provide controls for immunologic studies.
Objectives:
Primary Objective: to understand the mechanisms driving eosinophilia and eosinophil activation in patients with a wide range of eosinophilic disorders
Secondary Objectives:
Exploratory Objectives:
Endpoints:
Primary Endpoint:
Identification and characterization of clinical and genetic variants of hypereosinophilic syndromes (HES)
Secondary Endpoints:
1. Identification of laboratory and clinical tests that distinguish between clinical and genetic variants of HES
2a. Identification of biomarkers of disease activity and specific organ involvement in eosinophilic disorders
2b. Identification of new therapeutic targets for the treatment of HES
3. Delineation of the effects of therapeutic agents on eosinophil development, activation, recruitment to tissues and/or apoptosis
4. Creation of a patient-related outcomes questionnaire for use in future treatment studies of HES
Exploratory Endpoints:
Description of the consequences of eosinophilia and/or eosinophil depletion in the context of varied immunologic and inflammatory
settings
1,055 studies on the registry are indexed under Hypersensitivity; 149 are open to participants now.
This study's planned enrollment of 800 is above the median of 166 across 327 observational studies indexed under Hypersensitivity.
Browse Hypersensitivity studies →National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.
Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.
Compared within Hypersensitivity, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Immune System Diseases. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Participants with marked eosinophilia, eosinophilia in tissues or suspected eosinophilic end organ involvement will be seen on this protocol. Evaluation of family members may be of interest when a genetic cause of eosinophilia in suspected in a study participant.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
To be eligible to participate in this study, an individual must meet all of the following criteria:
Ability of subject (or Legally Authorized Representative (LAR)) to understand and sign a written document
Eosinophilic Patients only:
Primary (non-NIH) physician for routine medical care
Relatives only:
EXCLUSION CRITERIA:
An individual who meets any of the following criteria will be excluded from participation in this study:
Any condition(s) or diagnosis, physical and/or psychological, that the investigator feels precludes the patient from participation in the study.
Relatives only:
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.
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.
Volunteers with elevated eosinophil counts in the peripheral blood or tissues; or a relative of a volunteer with eosinophilia
To understand the mechanisms driving eosinophilia and disease pathogenesis in patients with a wide range of eosinophilic disorders
Identification and characterization of clinical and genetic variants of hypereosinophilic syndromes.
Time frame: Ongoing assessment
To assess the signs and symptoms experienced by patients with HES
Creation of a patient-related outcomes questionnaire for use in future treatment studies of HES
Time frame: Ongoing
To understand the mechanisms of action of therapeutic agents used or in development for the treatment of HES
Delineation of the effects of therapeutic agents on eosinophil development, activation, recruitment to the tissues and/or apoptosis
Time frame: Ongoing
To determine the mechanisms underlying eosinophil activation and recruitment to the blood and tissues
Identification of biomarkers of disease activity and specific organ involvement in eosinophilic disorders; identification of new therapeutic targets for the treatment of HES
Time frame: Ongoing
To develop a diagnostic algorithm that accurately classifies eosinophilic patients by underlying etiology
Identification of laboratory and clinical tests that distinguish between clinical and genetic variants
Time frame: Ongoing
Plan to share: Undecided
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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