The purpose of this protocol is to carry out laboratory studies concerning the immunopathogenesis of Common Variable Immunodeficiency (CVI) and related primary humoral immunodeficiency diseases. Additionally, we aim to document and track the progression of known complications of this primary immunodeficiency. Complications associated with CVID include recurrent respiratory, and gastrointestinal bacterial infections, pulmonary insufficiency, nodular regenerative hyperplasia, lymphoid malignancy, and various autoimmune manifestations.