This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this ongoing study is to evaluate the immune status of patients with primary immunodeficiency disorders. One aspect of this investigation, and the only subject of this application, is to measure the antibody responses to the T cell-dependent neoantigen, Bacteriophage fX174, which allows assessment of antigen clearance, the primary IgM response and the secondary response that determines amplification, class switch recombination and somatic hypermutation. Use of Bacteriophage is, in most instances, diagnostic and very rarely research. Since Bacteriophage is controlled by the FDA and has an IND number, we need to obtain consent from all patients independent of its use as a diagnostic tool or as a research tool. The response to Bacteriophage will help us to determine the need for immunoglobulin therapy or, in some cases, for bone marrow transplantation (BMT). Following successful BMT, Bacteriophage fX174 immunization may be used to determine if the marrow recipient's immune system has been fully reconstituted and if it is safe to give standard childhood immunizations. To assess a 'mature' immune response to this T cell-dependent antigen, each patient is immunized with a primary injection followed by booster injections (up to three or four times) with this antigen by the intravenous route. The standard dose is 0.02ml/kg body weight. Samples (usually 2.5 - 5ml of blood) are drawn before and after the phage immunization and analyzed for neutralizing antibody content. In order to be selected for immunization with Bacteriophage, patients are either known or suspected to have an antibody deficiency. This antigen is especially useful in individuals on IVIG because recall antigens cannot be used if an individual receives immunoglobulin infusions. Our standard protocol requests that samples of blood are obtained for antibody analysis at one, two and four weeks post immunization.
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