Mechanisms of Immune Deficiency

1. The purpose of this study is to learn more about the changes in genes, cells and proteins that cause immune deficiency diseases. 2. The early stages of the study will focus on two groups of patients: 1. members of families in which several persons have symptoms or medical histories that suggest immune deficiency. 2. Patients who have received treatments with medications or drugs that affect functions of the immune system (secondary immune deficiencies). It is hoped that studies will provide guidelines for extension of the research to other patient groups. Up to 200 patients and family members will be invited to participate.