INCLUSION CRITERIA:
Samples from patients with known or suspected primary immunodeficiencies, including those treated with stem cell transplants or gene correction therapy, and their families will be accepted worldwide primarily from tertiary care centers that treat patients with such immunodeficiencies.
Such patients will have documented evidence of either opportunistic infection, recurrent infection, or unusually severe responses to infectious agents that cause mild illness in unaffected individuals.
Either patient-derived B cell lines or primary blood samples will be accepted although in some cases buccal swabs will also be accepted.
Samples will not be obtained from unaffected children.
Infants with SCID or other primary immunodeficiency will not be seen; their physicians will care them for and only clinical material will be sent on such patients.
Medically stable patients with mild to moderate immunodeficiency may be seen at the NIH.
EXCLUSION CRITERIA:
Inability to provide informed consent.
A presence of any medical condition that would, in the opinion of the investigators, confuse the interpretation of the study (e.g., HIV infection).