This study is trying to find out if an undetectable serum immunoglobulin E (IgE) is a biomarker, or early sign of, the development of immune deficiency.

IgE is the antibody thought to be responsible for developing allergies. Undetectable serum IgE (an IgE below the lower limit of detection) is found in about 3% of the general population. In the past, it has been thought that having an undetectable IgE does not have any health impact, other than meaning that you are at low risk for having allergies. However, recent studies of patients with undetectable IgE have shown higher rates of infections, autoimmune disease and cancer.

Patients with an immune deficiency called common variable immunodeficiency (CVID) also have higher rates of infections, autoimmune disease and cancer. Recently, we have shown that most patients with CVID have a low/undetectable serum IgE.

This study is trying to find out if an undetectable serum IgE is a biomarker, or early sign of, the development of CVID or other antibody deficiencies

Inclusion Criteria:

• Age 18-80
• Willingness and ability to comply with scheduled visits and study procedures
• Undetectable serum IgE (defined as >2 IU/mL or the lower threshold of detection)
• Normal or high serum immunoglobulins (within or above laboratory reference range for IgG, IgA, and IgM)
• patients previously seen at the University of Virginia Asthma, Allergy, and Immunology clinics where undetectable serum IgE was noted
• Control subjects must have participated in study IRB#14457 (only applicable for healthy controls in epsilon germline transcript portion of the study)

Exclusion Criteria:

• The following vulnerable populations will be excluded: pregnant women, fetuses, neonates, children, prisoners, cognitively impaired, educational or economically disadvantaged, non-English speaking subjects
• Known personal history of immunodeficiency
• Known personal history of recurrent infections
• Low serum immunoglobulins (below the laboratory reference range for IgG, IgA, or IgM)
• Recent or current treatment with systemic immunosuppression within the past 30 days

De-identified IPD that underlie results in a publication will be made available upon request of another researcher or if required by the publisher

Starting 6 months after publication