Eosinophil Activation and Function in Parasitic Infections and Other Conditions With Increased Tissue or Peripheral Blood Eosinophilia in Humans

Official Summary

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: * Annual Follow-up evaluations - Physical examinations and blood tests to evaluate changes in the patient's condition and eosinophil counts over time. * Bone marrow biopsy and aspiration will be recommended during the initial evaluation, and in certain patients at other times when it is important to look directly at the newly developing cells in the bone marrow. For this procedure an area of skin and bone is anesthetized

Study Design

• Study Type: OBSERVATIONAL
• Enrollment: 800 participants

Primary Outcomes

• To understand the mechanisms driving eosinophilia and disease pathogenesis in patients with a wide range of eosinophilic disorders (Ongoing assessment)

Secondary Outcomes

• To assess the signs and symptoms experienced by patients with HES (Ongoing)
• To understand the mechanisms of action of therapeutic agents used or in development for the treatment of HES (Ongoing)
• To determine the mechanisms underlying eosinophil activation and recruitment to the blood and tissues (Ongoing)
• To develop a diagnostic algorithm that accurately classifies eosinophilic patients by underlying etiology (Ongoing)

Eligibility Criteria

* INCLUSION CRITERIA:

To be eligible to participate in this study, an individual must meet all of the following criteria:

1. Stated willingness to comply with all study procedures and availability for the duration of the study
2. Male or female, aged 1-100
3. Ability of subject (or Legally Authorized Representative (LAR)) to understand and sign a written informed consent document

   Eosinophilic Patients only:
4. Documented peripheral blood count \>1500/mm3, tissue eosinophilia (abnormal accumulation of eosinophils in the skin or other body tissues) or suspected eosinophilic end organ involvement
5. Primary (non-NIH) physician for routine medical care

   Relatives only:
6. Extended family member of an eosinophilic participant on this protocol

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Any condition(s) or diagnosis, physical and/or psychological, that the investigator feels precludes the patient from participation in the study.

   Relatives only:
2. Females must not be pregnant

Trial Locations

• National Institutes of Health Clinical Center, Bethesda, Maryland, United States

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