Primary Immunodeficiency


When part of the immune system is either absent or its function is hampered, an immune deficiency disease may result. The Primary Immunodeficiency Diseases are a group of disorders caused by basic defects in immune function that are inherent in the body. Some are relatively common, while others are relatively rare. Although there are some that affect a single cell or protein of the immune system, others may affect more than one component of the immune system. Although primary immune deficiency diseases may differ from one another in many ways, they share one important feature. They all result from a defect in one of the functions of the normal immune system.

The primary immune deficiencies result from defects in T-lymphocytes, B-lymphocytes, phagocytic cells or the complement system. Most of them are inherited diseases and may run in families, such as X-linked agammaglobulinemia (XLA) or Severe Combined Immunodeficiency (SCID). Other primary immune deficiencies, such as Common Variable Immunodeficiency (CVID) and Selective IgA Deficiency do not appear to be inherited in a clear cut or predictable fashion. In these disorders the cause is unknown but the interaction of genetic and environmental factors may play a role in their causation.