Primary agammaglobulinemias are a group of rare immune deficiencies characterized by a lack of antibodies to fight disease and by dysfunction of B lymphocytes (specialized white blood cells that produce antibodies). Other names for this syndrome include antibody deficiency, gammaglobulin deficiency, and immunoglobulin deficiency. There are many subdivisions of primary agammaglobulinemia that describe the specific deficiency in a given patient. Acquired immunodeficiency syndrome (AIDS) is perhaps the most well known of these subdivisions.