PLCG2-associated antibody deficiency and immune dysregulation (PLAID) is a disorder of the immune system involving a mild allergic reaction to colder temperatures. It was identified in 2012 and has been seen in a small number of people since then. There are not a lot of known cases and new knowledge about PLAID is still being discovered. PLAID is characterised an immune system that is not fully functional, hives, and skin lesions.
Autoimmune diseases occur when the body’s immune system fails to recognize the body as a non-foreign object and attacks it. Autoimmune diseases can cause a variety of symptoms depending on what tissues the body attacks. Immune system function reduction in PLAID is associated with a lack of working antibodies. Antibodies are proteins produced by the immune system that attach to foreign objects, like bacteria or viruses, and signal that they should be destroyed.
The primary symptom of PLAID is called cold urticaria, or hives that develop when someone with PLAID is exposed to cold temperatures. Cold urticaria can be caused by cold air temperatures, a breeze passing by, or from water or sweat evaporating off of the skin. Other symptoms of PLAID include:
Autoimmune Lymphoproliferative Syndrome (ALPS)
Caspase Eight Deficiency State (CEDS)
CARD9 Deficiency And Other Syndromes Of Susceptibility To Candidiasis
Chronic Granulomatous Disease (CGD)
Common Variable Immunodeficiency (CVID)
Congenital Neutropenia Syndromes
Hyper-Immunoglobulin E Syndromes
Hyper-Immunoglobulin M Syndromes
Interferon Gamma, Interleukin 12 And Interleukin 23 Deficiencies
Leukocyte Adhesion Deficiency (LAD)
Severe Combined Immunodeficiency (SCID)
STAT3 Dominant Negative Disease (STAT3DN)
STAT3 Gain-Of-Function Disease (STAT3 GOF)
Warts, Hypogammaglobulinemia, Infections, And Myelokathexis (WHIM) Syndrome
Wiskott-Aldrich Syndrome (WAS)
X-Linked Agammaglobulinemia (XLA)
X-Linked Lymphoproliferative Disease (XLP)
Immunodeficiency Disease Medications
PLAID is caused by a change, or mutation, in the PLCG2 gene. This gene helps the cells in the immune system recognize foreign objects and distinguish them from the body. The changes to the PLCG2 gene affect the region of the gene that controls when the gene is active and when it is inactive. The changed gene does not work properly at different temperatures. At lower temperatures, the gene is always on, causing the immune symptoms associated with PLAID.
At a normal body temperature, the gene is underactive, meaning the immune system cannot do its job properly. PLAID is typically inherited from a parent with the mutation. A child gets two copies of every gene, one from the mother and one from the father. Only one PLCG2 gene needs to be changed for PLAID to be present. It is possible for the change in the PLCG2 gene to happen suddenly in a child who doesn’t have a parent with PLAID.
Your doctor may want to test for PLAID based on disease history in your family or medical exam findings. Genetic testing is the only definitive way to make a diagnosis of PLAID.
Complications of PLAID include:
Treatment for PLAID involves targeting the symptoms that each individual experiences. Those with PLAID are advised to avoid exposure to cold temperatures and drafts and to quickly warm themselves up after being in the water. Anti-allergy medications are used to manage hives and other allergic reactions. Hormone replacement therapy can be used to treat autoimmune thyroiditis and immune therapies can be used to treat vitiligo. Infections are treated as they arise.