The purpose of this study is to evaluate patients with primary immunodeficiency disorders to identify patients with mutations of the genes for the following proteins: Jak3, STAT1, STAT4, interleukin-7, interleukin-7 receptor, interleukin-12 receptor subunits, and others. Patients will undergo screening history, physical examination, and clinical laboratory evaluation at referring institutions and tissue samples, or cell lines will be sent to the NIH. We will establish cell lines if necessary, prepare DNA and RNA for molecular genetic analysis and study cytokine signal transduction in patient cell lines.