What is a Primary Immunodeficiency Disease?
Nearly everyone has suffered from colds, the flu, or sinus and ear infections. Just as many have been affected by cuts, scrapes and abrasions that become infected. Even in the case of more severe infections—such as pneumonia—we expect the cough and congestion to ‘run its course’, aided by prescription antibiotics, over-the-counter symptom remedies, and our body’s own immune system.
Recovery times vary, but the human body can usually rid itself of the infection-causing germs, and work to defend against future “bugs” and viruses. There are, however, instances in which the body cannot recover, and some of these apply to individuals with a primary immunodeficiency disease.
Primary immunodeficiency diseases occur in persons born with an immune system that is either absent or hampered in its ability to function. While not contagious, these diseases are caused by hereditary or genetic defects and can affect anyone, regardless of age or sex. The World Health Organization recognizes more than 150 primary immunodeficiency diseases—some are relatively common, others are quite rare. Some affect a single cell within the immune system; others may affect one or more components of the system.
And while the diseases may differ, they all share one common feature: each results from a defect in one of the functions of the body’s normal immune system. Because one of the most important functions of the normal immune system is to protect us against infection, patients with primary immunodeficiency diseases commonly have an increased susceptibility to infection.
The infections may be in the skin, the sinuses, the throat, the ears, the lungs, the brain or spinal cord, or in the urinary or intestinal tracts, and the increased vulnerability to infection may include repeated infections, infections that won’t clear up or unusually severe infections. People with primary immunodeficiency diseases live their entire lives more susceptible to infections—enduring recurrent health problems and often developing serious and debilitating illnesses. Fortunately, with proper medical care, many patients live full and independent lives.
Is it just an infection?
Do the same symptoms keep coming back or never seem to completely clear? Is the infection severe enough to require hospitalization or intravenous antibiotics? Is there a family history of early infant death or of susceptibility to infection?
If you answered yes to any of these questions it is critical to get an early diagnosis and proper medical care – don’t hesitate call us to check for the possibility of a primary immunodeficiency disease.
The Immune System and Primary Immunodeficiency Diseases
When part of the immune system is either absent or its function is hampered, and immune deficiency disease may result. An immune deficiency may be caused either by an intrinsic (inborn) defect in the cells of the immune system or an extrinsic (coming from the outside) environmental factor or agent. In the case of an inborn or congenital defect, the immune deficiency disease is a primary immune deficiency disease. When the damage is caused by an extrinsic force, such as an environmental factor or agent, it is called a secondary immune deficiency disease. For example, AIDS is a secondary immune deficiency disease caused by the HIV virus. Secondary immune deficiencies can also be caused by irradiation, chemotherapy, malnutrition, and burns. The secondary immune deficiencies are not discussed in this handbook.
The primary immunodeficiency diseases are a group of disorders caused by basic defects in immune function that are intrinsic to, or inherent in, the cells and tissues of the immune system. There are over 150 primary immunodeficiency diseases. Some are relatively common, while others are quite rare. Some affect a single cell or protein of the immune system and other s may affect more than one component of the immune system. Although primary immunodeficiency diseases may differ from one another many ways, they share on important feature, They all result from a defect in one of the functions of the normal immune system. The primary immunodeficiencies result from defects in T-lymphocytes, B-lymphocytes, NK cells, 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 immunodeficiencies, such as Common Variable Immunodeficiency (CVID) and Selective IgA Deficiency are not always 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. Because one of the most important functions of the normal immune system is to protect us against infection, patients with primary immunodeficiency diseases commonly have an increased susceptibility to infection. This increased susceptibility to infection may include too many infections, infections that are difficult to clear, or unusually severe infections. The infections may be located in the sinuses (sinusitis), the bronchi (bronchitis), the lung (pneumonia) or the intestinal tract (infectious diarrhea). Another function of the immune system is to discriminate between the individual (“self”) and foreign material (“non-self”), such as microorganisms, pollen or even a transplanted kidney from another individual. In some immunodeficiency diseases, the immune system is unable to discriminate between “self” and “non-self.”
Therefore, in addition to an increased susceptibility to infection, patients with immune deficiencies may have autoimmune diseases in which their immune system attacks their own cells or tissues as if they were foreign or “non-self.” There are also a few types of immune deficiencies in which the ability to respond to an infection is intact, but the ability to regulate that response is abnormal. Examples of this are autoimmune lymphoproliferative syndrome (ALOS) and IPEX (immunodeficiency, polyendocrinopathy, X-linked syndrome).
Primary immunodeficiency diseases can occur in individuals of any age. The original descriptions of these diseases were in children, but as medical experience has grown, many adolescents and adults have been diagnosed with primary with primary immunodeficiency diseases. This is partly due to the fact that some of the disorders, such as Common Variable Immunodeficiency Disease and Selective IgA Deficiency, may have their initial clinical presentation in adult life. Another factor is that effective therapy exists for nearly all of the disorders and patients who were diagnosed in infancy and childhood now reach adult life as productive member of society.
Finally, the primary immunodeficiency diseases were originally felt to be very rare. However, they are common than originally thought. In fact, Selective IgA deficiency, occurs as often as one in 500 individuals, translating into 500,000 patients in the United States alone. With so many individuals affected with primary immunodeficiencies, it is no surprise that research in the field of immunology is advancing rapidly. Each year brings better diagnostic strategies, and hope for more cures.