| Immune System Disorders / Recurrent Infections
Immune system disorders occur when part of the immune system is either absent or not functioning properly. When the cause of this abnormal immune system is hereditary or genetic, it is called a primary immunodeficiency disorder (PIDD), otherwise it is called secondary immunodeficiency disorder.
The immune system is composed of various kind of cells which protect and defend against germs, bacteria and fungi. In immunodeficiency disorders, different forms of these cells are missing. This leads to recurrent, severe infections, which are unusually hard to treat. These infections may attack the skin, respiratory system, the ears, the brain or spinal cord, or the urinary or gastrointestinal tracts. There is also an increased risk for autoimmune disease and malignancy.
Primary Immunodeficiency Disease (PIDD)
PIDDs typically presents in infancy. However, in mild cases, it often takes a series of recurrent infections before PIDD is suspected. Important signs that suggest PIDD are as follows:
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Recurrent infections, that are difficult to treat
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Failure to thrive or loss of weight
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Recurrent ear or sinus or lung infections
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Multiple courses of antibiotics or IV antibiotics necessary to clear infections
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Recurrent deep abscesses of the skin or other organs (e.g. liver)
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Family history of immunodeficiency disorder
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Swollen lymph glands or an enlarged spleen
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Autoimmune disease
Classification of PIDDs
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Antibody Deficiencies are the most common cause of PIDD, the names of some of the major ones are common variable immune deficiency (CVID), IgG subclass deficiency, selective IgA deficiency, functional antibody deficiency (a.k.a. selective antibody deficiency), X-linked agammaglobulinemia.
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Cellular Immune Deficiency – Includes T-, B- and NK cell disorders
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Phagocytic Cell Deficiency include Hyper IgE syndrome, autosomal recessive (p47phox) chronic granulomatous disease, IL-12 and interferon gamma receptor (IFNγR) pathway defects
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Complement Deficiency