Hypereosinophilic Syndrome

Background: Hypereosinophilic syndrome (HES) is a blood disorder that causes high levels of white blood cells called eosinophils. HES can damage the lungs and airways, intestines, skin, and other organs. The current primary treatment for HES can cause serious side effects. Secondary treatments do not work in all people. Objective: To test an approved drug (dupilumab), combined with other drugs, in people with HES. Eligibility: People aged 18 years and older who take drugs (mepolizumab, reslizumab, or benralizumab) to treat HES. Design: Participants will have up to 6 clinic visits and 7 remote visits in up to 48 weeks. Participants will be screened. They will have blood and urine tests. They will have a test of their heart function. They will take surveys about how HES affects their daily life. Some participants may have a bone marrow biopsy: A sample of tissue and fluid from inside a bone will be removed with a large needle. Participants will have other tests specific to their symptoms. For example, those with symptoms affecting their lungs will have breathing tests. Others may have tests that target symptoms in their sinuses, gastrointestinal tract, or skin. Dupilumab is injected under the skin once every 1 or 2 weeks. Dose and timing will vary among participants. They will be taught how to inject themselves at home between clinic visits. They will take dupilumab plus their current medications for 24 weeks. If the drug is helping them, they will continue taking it for another 24 weeks. Participants will have a final visit 12 weeks after their last dose.

Eosinophils are a type of white blood cell. Elevated eosinophil levels can damage the heart, nerves, and other organs, in the syndrome known as hypereosinophilic syndrome (HES). Some individuals have a hereditary form of HES known as familial eosinophilia (FE). More research on the causation and mechanisms of HES is needed in order to design more effective and less toxic therapies. This study will investigate FE and its genetic causes, damage mechanisms, and disease markers (such as blood test abnormalities). It will enroll approximately 50 individuals (both adults and children) from a previously studied family with FE. This is a long-term study of indefinite duration. Participants will undergo yearly clinical examinations including medical history, physical examination, bloodwork, EKG, echocardiogram, and pulmonary function tests, with additional or more frequent examinations and tests as required. In addition, participants will donate blood and tissue for research purposes. Both adult and child participants will donate blood. At the initial evaluation, adult participants will donate bone marrow. During the study, some adult participants will also undergo a limited number of leukaopheresis sessions, in which blood is donated from one arm, the blood is separated into red blood cells and other components, and the red blood cells are returned into the donor's other arm.

Unexplained chronic hypereosinophilia (HE) and hypereosinophilic syndromes (HES) are heterogeneous regarding the organ involvements (heart, lungs, skin, .. or none), the evolutionary profiles, the response to treatments. Underlying mechanisms are largely unknown and may associate genetic predisposing factors (germinal ? somatic?), environmental factors (alimentation, tobacco use, hormones, infections, ..) The COHESion study aims to study all clinical and biological characteristics of HE/HES patients and their evolutionary profiles, with a focus on genetic factors and the mechanisms supporting transitory or persistant chronic HE/HES (in absence of any well identified extrinsic trigger like drugs, parasitosis, ..)