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About
Primary Immune Deficiency

What is Primary Immune Deficiency?

Primary immune deficiency is actually the name for a group of over 100 diseases that:

• Are usually inherited
• Are caused by errors in the genes of the cells that make up the immune system
• Have a wide range of symptoms from mild to severe

People with primary immune deficiency (PI) have an immune system that does not function correctly. The immune system protects the body from germs like bacteria and viruses which cause the infections that make people sick. When any part of a person's immune system is missing or not functioning correctly, he or she is more likely to get infections and to take longer to recover from infections.

How do you get PI?

Primary Immune Deficiency disease occurs when one or more of the organs, tissues, cells, or proteins of the body's immune system is missing or is not functioning properly because of a genetic defect.

Genes carry instructions like a blueprint for forming the body. Small changes or mutations in just one gene can lead to immune system defects and diseases. One or both parents may carry a defective gene. When the child inherits such a gene, the developmental errors in the immune system can result in different types of PI.

What are the symptoms of PI?

The most common symptom for most of the primary immune deficiency diseases is susceptibility to infection. People with PI get infections more often, take longer to recover, even with antibiotic treatment, and are more likely to have recurring infections.

These symptoms can often be seen early on in the child's life. However, signs and symptoms of immune disease may also occur in older children, teenagers, or adults. Primary immune deficiency diseases can range from mild to very serious conditions.

What are the characteristics of PI?

Currently the World Health Organization lists over 100 PIs and the numbers are increasing. PIs differ from one another in many ways. Some types of PIs are characterized by a defect in one or more of the functions of the normal immune system, such as certain types of white blood cells (T cells, B cells, phagocyte cells), or the complement system (a system of proteins that helps defend against infection). The cells and proteins of the immune system directly impact how antibodies are made and how effectively they do their job to fight off invading germs, or ‘pathogens.' When certain cells of the immune defense system are missing, individuals are vulnerable to specific types of diseases.

How Is Primary Immune Deficiency different from AIDS?

AIDS is short for Acquired Immune Deficiency Syndrome. Acquired means that the disease cannot be inherited. HIV, the virus that is responsible for causing AIDS, can be passed from an infected person to an uninfected person through certain body fluids. Only when a person becomes infected with this virus is the immune system damaged.*

Primary Immune Deficiency is different from AIDS because it is a genetic disease and may be present from birth. It is not transferred from one person to another.

How Is Primary Immune Deficiency different from Leukemia?

Leukemia is a cancer that originates in the bone marrow and can be described as the uncontrolled growth of cells. The disease results from an acquired (not inherited) genetic injury to the DNA of a single cell which becomes abnormal (malignant) and multiplies continuously. The accumulation of malignant cells interferes with the body's production of healthy blood cells and makes the body unable to protect itself against infections.**

Primary Immune Deficiency is different from leukemia because it can be inherited and occurs when one or more important parts of the immune system is missing or not functioning properly.

*National Institutes of Child Health and Human Development. National Institutes of Health. When the Body's Defenses are Missing: Primary Immunodeficiency. NIH Pub No. 99-4149: p3.

**The Leukemia and Lymphoma Society, 1311 Mamaroneck Ave., White Plains, NY 10605