Idiopathic CD4+ Lymphocytopenia clinical trials

Etiology, Pathogenesis, and Natural History of Idiopathic CD4+ Lymphocytopenia

Background: - Idiopathic CD4+ lymphocytopenia (ICL) is a condition in which there is a decreased level of CD4+ lymphocytes (a type of white blood cell), which can lead to opportunistic infections or autoimmune disorders and diseases. Objectives: - To characterize the natural history with regard to CD4+ T cell count and onset of infection, malignancy, and autoimmunity. - To describe the immunological status of patients affected by ICL while providing the best possible standard therapy to eradicate opportunistic infections. - To establish the timeline of CD4 lymphocytopenia, with particular focus on defining subgroups of patients according to the decline, stabilization, or rise of CD4+ T cell counts over time. - To characterize the opportunistic infections that occur in ICL patients at microbiologic and molecular levels. - To characterize the immunophenotype and possible genetic immunodeficiency causes of ICL. - To determine whether measurable immunologic parameters correlate with the development of opportunistic infections or other comorbidities such as lymphoma in patients with ICL. - To determine whether there is any association between ICL and autoimmunity. - To determine CD4+ T cell turnover, survival, functionality, and cytokine responsiveness in ICL patients. Eligibility: - Patients 2 years of age and older with an absolute CD4 count less than 300 in children 6 years or older and adults or less than 20% of T cells in children younger than 6 on two occasions at least 6 weeks apart. - Patients with negative results of HIV testing by ELISA, Western Blot, and viral load. - Patients must not have underlying immunodeficiency conditions, be receiving cytotoxic chemotherapy (anti-cancer drugs that kill cells), or have cancer. Design: - At the initial visit to the National Institutes of Health, the following evaluations will be conducted: - Personal and family medical histories. - Physical examination, including rheumatology evaluation and other consultations as medically indicated (e.g., dermatology, pulmonology, ophthalmology, imaging studies). - Blood samples for analysis of red and white blood cell counts, liver function, immune hormones, and antibody and autoantibody levels, white blood cell growth and function, and DNA. - Urinalysis and urine pregnancy testing for female patients of childbearing age. - Evaluation and treatment of active infections as medically indicated, including biopsies, buccal swabs, pulmonary function tests, and imaging studies. - Follow-up visits will take place approximately every 12 months or more frequently if indicated, and will continue for a minimum of 4 years and a maximum of 10 years. - Evaluations at follow-up will include blood samples (i.e., CBC with differential, biochemical profile, HIV testing, etc.) and urinalysis and rheumatology consults.