Patients with a clinical history or signs and symptoms suggestive of a primary immune deficiency syndrome and their family members are eligible for inclusion in this study and they may be referred by their physician or self-referred. If possible, a local physician/clinical immunologist will be identified for self-referred patients to serve as primary reference. If screening of the patients, either by phone interview or review of their medical records indicates that the patient may have a primary immunodeficiency syndrome and is HIV-negative, the patient will be invited to come to the NIH and sign an informed consent. If family history is positive for immunodeficiency, the patients or family members may be asked to invite other relatives to contact the PI to participate in the study.