Selective IgA deficiency is a condition that affects the immune system. It occurs when the immune system does not have or does not produce enough of an immunoglobulin known as immunoglobulin A (IgA). IgA is a type of protein produced in the body that is designed to fight off infections and is also called an antibody. Selective IgA deficiency is by far the most common immune deficiency disorder.
IgA is just one of the types of immunoglobulins produced in the human body. There are five types in total. IgA is often present in relatively large amounts in the body, particularly in mucosal secretions such as in the nasal passages. While selective IgA deficiency may cause a person to be more prone to developing infections or certain types of infections, this is not always the case.
Generally, selective IgA deficiency is a condition that is inherited. Caucasian people (people of European descent) are more likely to suffer from this immune system condition than other demographic groups. Additionally, selective IgA deficiency can be passed down by either one or both parents to their offspring (an autosomal recessive or autosomal dominant inheritance pattern). There have also been causes in which this condition was caused by drugs or medications (known as drug-induced selective IgA deficiency).
Some people who have selective IgA deficiency show no symptoms. The condition may be discovered during routine blood work or when a physician is looking for signs of other conditions. However, there are some people who do show signs of the condition. If a person suffers from asthma of an unknown cause or origin, it may be a sign that they suffer from selective IgA deficiency. Having chronic bronchitis, sinusitis, otitis media (middle ear infections), and pneumonia can also be indicative of selective IgA deficiency.
Selective IgA deficiency occurs when individuals lack immunoglobulin A, a type of antibody in the blood. Usually, this is a genetic trait inherited from biological parents, which means that those with a family history of the disorder are at an increased risk of having it themselves.
It is possible to inherit selective IgA deficiency as an autosomal dominant or recessive trait. Autosomal dominant traits are caused by an abnormal gene inherited from just one parent, even if the other parent has a normal equivalent gene. With autosomal recessive traits, both parents must have an abnormal gene for the trait to be inherited by their child.
In rare cases of selective IgA deficiency, the condition has been drug-induced. Drugs which are known to induce the deficiency include:
There is no specific treatment for selective IgA deficiency. Most treatments are focused on managing any infections that occur due to this immunoglobulin deficiency. Bacterial infections are to be treated with antibiotics as they occur. If a person has chronic bronchitis or sinusitis, it may also be necessary for a person to be on prophylactic (preventive) antibiotics on a long-term basis. Blood transfusions or other blood products are not recommended and should be used in emergency situations with extreme caution as a person with IgA deficiency may have IgA antibodies in their blood that could cause an allergic reaction and anaphylaxis if IgA is introduced into the bloodstream.
Since selective IgA deficiency is usually an inherited trait, it isn’t possible to prevent it. However, it may be possible to prevent frequent infections which tend to occur as a result of the disorder.
Many infections are caused by bacteria or viruses which enter the body via mucous membranes. To reduce the risk of contracting infections, good hygiene practices are vital. Hands should be washed regularly, particularly before eating and when in close contact with individuals who are contagious with an infection such as a cold or flu.
In some instances of selective IgA deficiency where patients suffer chronically from illnesses like sinusitis and bronchitis, long term use of preventative antibiotics may be recommended to reduce the frequency or severity of flare-ups. Immunoglobulin replacement therapy may also be recommended for some patients with the deficiency to prevent infection.