When part of the immune system is either absent or not functioning properly, it can result in an immune deficiency disease. When the cause of this deficiency is hereditary or genetic, it is called a primary immunodeficiency disease (PIDD). Researchers have identified more than 150 different kinds of PIDD.

Important signs that may indicate a PIDD include:

• Recurrent, unusual or difficult to treat infections
• Poor growth or loss of weight
• Recurrent pneumonia, ear infections or sinusitis
• Multiple courses of antibiotics or IV antibiotics necessary to clear infections
• Recurrent deep abscesses of the organs or skin
• A family history of PIDD
• Swollen lymph glands or an enlarged spleen
• Autoimmune disease