Hypogammaglobulinemia is a disorder in which the body’s immune system does not make antibodies, or makes a reduced amount. It has a variety of causes, but the most common is a primary immune deficiency, usually the result of a genetic mutation that prevents the immune system from making antibodies.
In a healthy immune system, cells called B lymphocytes make antibodies in response to bacterial and viral infection. Antibodies have a variety of roles, the most important of which is to destroy invading microorganisms. This is achieved through a process called opsonization, in which antibodies coat the microorganisms and make them vulnerable to destruction by other types of immune cells.
Someone with hypogammaglobulinemia, therefore, is highly susceptible to bacterial infections, and to a lesser extent, viral infections. Symptoms such as chronic bacterial or viral infection such as colds, flu, tonsillitis, and sinusitis are common. Chronic diarrhea, inflammatory bowel disease, weight loss, and fatigue may also result. Children with this immune deficiency often fail to thrive, and may be underweight for their age, and smaller than their peers.
Many different conditions may cause antibody deficiency. One of the most widespread is called common variable immunodeficiency, or CVID. This immune deficiency can be caused by a range of different genetic mutations, each of which results in antibody defects that increase susceptibility to infection. Another antibody deficiency disease, called X-linked agammaglobulinemia, is a genetic disorder which is inherited on the X chromosome.
The most common treatment is regular injections of IgG immunoglobulin, also known as gammaglobulin. This is an antibody preparation that is extracted from donated blood. Gammaglobulin contains antibodies extracted from people who have been vaccinated against or exposed to common diseases, such as mumps, chickenpox, influenza, and bacterial infections. These antibodies provide what is known as passive immunity; it is passive because it has not been generated by the recipient’s own immune system.
This treatment is given every three to four weeks, for the remainder of the recipient’s life. It does not cure hypogammaglobulinemia, but reduces susceptibility to infection in people with the disorder. The recipient’s quality of life and lifespan are both markedly improved.
Gammaglobulin treatment can prevent many common infections, but not all can be avoided. People with antibody deficiencies will also generally take antibiotics in any case of bacterial infection, no matter how minor it may be. In the case of chronic infections, such as sinusitis or urinary infection, long-term treatment with antibiotics may be necessary.