B-Lymphocyte Stimulator (BLyS) To Treat Selective IgA Deficiency

This study will examine the safety of BlyS, an experimental drug being developed to treat immune deficiency. As of July 17, 2001, 7 persons with common variable immune deficiency (CVID) have received BlyS, with no problems reported. This study will test the safety of the drug in people with IgA deficiency. Patients 18 years of age and older with IgA deficiency who have recurrent or chronic sinus or lung infections or chronic diarrhea or malabsorption may be eligible for this study. Candidates will be screened with a physical examination, blood and urine tests, electrocardiogram (EKG), chest X-ray and a breathing test (spirometry). Participants will be divided into five groups of three persons each to receive different doses (0.1, 1, 5, 15 or 45 micrograms/kilogram of body weight) of BlyS. The first group will receive a single dose at the lowest dose level (0.l mg). Each succeeding group will receive a single higher dose following a 2-week observation period of the preceding group. The drug will be injected under the skin, with vital signs (temperature, pulse, blood pressure and breathing rate) monitored for one hour after dosing. Blood samples will be collected several times on the day of dosing (before the dose and at 1.5, 3, 5, 8 and 12 hours after the dose) and again at 1,2, 4, 8 and 12 weeks after the dose to measure BlyS levels and evaluate safety. Participants receiving one of the three higher doses will have additional blood samples collected 36, 48 and 60 hours after the dose. Blood will also be collected from all participants 6 and 12 months after dosing to look for any unexpected long-term effects. A total of 289 ml (1.2 cups) of blood will be collected. Blood will be checked for changes in blood count, kidney and liver function, antibody levels and autoimmune problems. Saliva will be collected four times by placing a cotton ball in the mouth-once before the dose and three times after the dose-to measure antibody levels. Urine samples will also be coll