Amanda has taught high school science for over 10 years. They have a Master's Degree in Cellular and Molecular Physiology from Tufts Medical School and a Master's of Teaching from Simmons College. They also are certified in secondary special education, biology, and physics in Massachusetts.
What Are Immunoglobulins?
When you're sick, a war rages inside your body. Bacteria and viruses, known as pathogens, battle in your throat and lungs for entry into your body. They want the nutrients and space that your body works hard to produce and maintain, but the tissues in your body aren't going down without a fight.
A large component of your immune system are the white blood cells ,which are the soldiers of your body, combating invading pathogens. There are different types of white blood cells in your body, but B-cells are the type that will be the focus of our lesson today. B-cells are white blood cells that make special proteins called immunoglobins, also known as antibodies, that attach to pathogens and alert the immune system. When B cells don't make enough of these antibodies the condition is known as an immunoglobulin deficiency.
Types of Immunoglobulin Deficiencies
The B-cells make different types of immunoglobulins depending on what the invader is. There are five main categories, immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin E (IgE), immunoglobulin M (IgM) and immunoglobulin D (IgD). Each immunoglobulin does a different job in the body, so there are different symptoms for each immunoglobulin deficiency, which is what we will cover next.
IgA is the main antibody used to protect the mucus coated surfaces in your body. Your intestines, lungs, reproductive and urinary tracts are all protected by mucus filled with IgA antibodies. It's an important front line for keeping pathogens that have access to these surfaces at bay. You can think of them as soldiers guarding the border.
People with IgA deficiency have trouble with respiratory infections such as bronchitis. Since IgA is located in the digestive system as well, these individuals suffer from irritable bowel syndrome and other intestinal infections. Anyone can get these infections, but people with an IgA deficiency tend to develop them more often.
There is no treatment for people with IgA deficiency, although some do develop IgA antibodies gradually over their lifetime. You might be thinking, couldn't we just give them more IgA antibodies? The answer, unfortunately, is no. The immune systems of people without IgA think that any new IgA donated is an invader, and try to destroy it. When that happens, the body can go into shock. An example of this would be getting a blood transfusion from the wrong blood type. Since the body never had IgA, the IgA appears foreign and triggers a full immune response, just like a bacteria or virus would.
IgG is the most common antibody, and circulates our blood. Thus, people without IgG antibodies have a wide range of infections like ear, sinus, lung and throat infections. Like with IgA deficiency, any infection can be treated with antibiotics. Usually, there are no additional treatments needed after taking antibiotics, but if the symptoms become severe or the infections become resistant to antibiotics, IgG replacement therapy can be used.
Unlike IgA deficiency, IgG antibodies can be purified from a donor's blood and given to the patient through an IV, or an injection under the skin. The patient doesn't usually go into shock as they would with IgA antibodies, but may have mild symptoms such as headaches or muscle soreness.
IgE is also found in mucus, and is involved in allergic reactions and getting rid of parasites. IgE deficiency has been studied less than other deficiencies like IgA and IgG, so there is less known about it. Some studies have found that having low IgE contributes to respiratory infections, and increased risk of autoimmune diseases, like in IgA deficiency. Usually patients complain of fatigue and respiratory infections. There is no way to replace IgE currently, so doctors usually treat the resulting illnesses as they would in a typical patient.
IgM is the first antibody made during an infection. Think of it like an emergency first responder. IgM signals for more specific IgG antibodies to be made en masse, and activates the rest of the immune system.
People with a deficiency in IgM have more bacteria, viral and fungal infections than people without the deficiency. Scientists have also found that low levels of IgM might contribute to the development of autoimmune diseases; when the immune system turns against the host and attacks the body. Doctors cannot replace IgM like they can for IgG antibodies because IgM is found in such small amounts in the blood. Like other immunoglobulin deficiencies, antibiotics can be used to treat infection.
Although the functions of other immunoglobulins are well studied, scientists are still not entirely sure about what IgD does in the body. There are people that have low levels of IgD, but they don't appear to have symptoms, such as increased infections as in other immunoglobulin deficiencies.
Immunoglobulin deficiencies occur when a person's B-cells can't make one or more of the five classes of antibodies. Each antibody has a specific job in our body, so the symptoms of each are different. IgA and IgE are found in mucus, like in the lungs, and people with these deficiencies are more susceptible to respiratory infections. People with IgA can not get foreign IgA to replace their antibodies because the body will reject it, and can go into shock. There is also no foreign IgE replacement available. Antibiotics are used to treat the symptoms of these two deficiencies. IgG antibodies are the most common and are present in the blood. Symptoms of a deficiency include a wide range of infections and can be treated with antibiotics or an IV of IgG antibodies. IgM is the first antibody made during an infection, and patients with this deficiency can develop autoimmune diseases. There is no replacement IgM available, but doctors can treat subsequent infections. Little is known about IgD deficiency.
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.Become a Member
Already a member? Log InBack