What is this study trying to find out about idiopathic CD4+ lymphocytopenia?

This study aims to understand the natural history and immune characteristics of idiopathic CD4+ lymphocytopenia, a condition with low CD4+ T cells not caused by HIV or other known causes. Researchers want to learn how the disease progresses, its relation to infections and autoimmune disorders, and potential genetic factors. The National Institute of Allergy and Infectious Diseases is leading this research.

Who may be eligible for this idiopathic CD4+ lymphocytopenia clinical trial?

Adults aged 18 years and older diagnosed with idiopathic CD4+ lymphocytopenia, having low CD4+ T cell counts, may be eligible. Participants must not have HIV or other known immunodeficiencies and should not be taking medications that lower CD4+ counts. Both blood relatives and household contacts of ICL patients may also participate. Please review eligibility criteria for more details.

Is there any cost to participate in this idiopathic CD4+ lymphocytopenia clinical trial?

Study-related care, including all evaluations and laboratory tests, is provided at no cost. However, personal expenses such as travel or accommodations may not be covered and can vary. Participants should plan accordingly for any costs related to attending study visits.

Actively Recruiting

Age: 18Years +

All Genders

Healthy Volunteers

ID00867269

Study of Idiopathic CD4 Lymphocytopenia ICL to Understand Causes, Immune Changes, and Risks of Infections and Autoimmune Diseases

Led by National Institute of Allergy and Infectious Diseases (NIAID) · Updated on 2026-08-07

950

Participants Needed

Research Sites

N/A

Total Duration

AI-Summary

What this Trial Is About

Idiopathic CD4 lymphocytopenia ICL is a disorder marked by low levels of CD4 T lymphocytes without an identifiable cause like HIV infection or other immunodeficiencies. This study aims to understand the natural history of ICL, examining changes in CD4 T cell counts and the development of infections, autoimmune diseases, or malignancies over time. Researchers also seek to explore the immune profile and possible genetic causes of ICL while providing standard care to manage infections. Participants include ICL patients as well as their blood relatives and household contacts. The study involves initial comprehensive evaluations including medical history, physical exams, various specialist consultations, blood tests for immune and genetic markers, urine tests, and infection assessments. Follow-up visits occur approximately every 12 months or more often if needed, continuing for at least 4 years and up to 10 years to monitor disease progression and immune status. During participation, patients undergo regular blood sampling to measure CD4 T cell counts and other immune parameters, along with evaluations for infections and autoimmune symptoms. Researchers also collect tissue samples and conduct genetic testing. The study measures outcomes such as CD4 levels, immune cell function, and correlations with infections or other health issues. Participants receive ongoing monitoring and treatment as appropriate, with the total involvement lasting from 4 to 10 years.

CONDITIONS

Brief Title

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

Who Can Participate

Age: 18Years +

All Genders

Healthy Volunteers

Eligibility Criteria

You may qualify if you...

Age greater than or equal to 18 years
Absolute CD4 count less than 300 cells/microL or less than 20% of total T cells on at least two occasions at least 6 weeks apart
Ongoing care by a referring primary care physician
Willingness to allow storage of blood and tissue samples for future analysis
Blood relatives of individuals who meet or have met the CDC criteria for ICL, aged 18 years or older
Household contacts living with an ICL subject, aged 18 years or older

You will not qualify if you...

Known infection with HIV-1, HIV-2, or human T-cell lymphotropic viruses (HTLV-1 or HTLV-2)
Known underlying immunodeficiency syndrome other than ICL
Evidence of active malignancy
Use of medications, herbal substances, or biologic agents known to lower CD4+ count within 30 days before detection of lymphocytopenia
Any condition that would place the subject at undue risk or affect study results as judged by investigators

Your Study Journey

Screening

Duration - 2 to 4 weeks

Participants are screened for eligibility to participate in the trial.

Initial Evaluation

Duration - 1 visit (in-person)

Participants undergo medical history review, physical exams, specialist consultations, and blood and urine tests to assess immune status and infections.

1 visit (in-person)

Follow-up Monitoring

Duration - Minimum of 4 years, up to 10 years

Participants return approximately every 12 months or more often if needed for blood tests and health evaluations to monitor disease progression and immune function.

Annual visits or more frequent as needed