Immunoglobulin G (IgG) is a component of blood plasma that is essential for the healthy function of the immune system. IgG helps neutralize bacteria, viruses, and environmental toxins before they can infect and damage cells in the body. A deficiency of IgG can leave a person susceptible to chronic and recurring infections, especially respiratory infections such as bronchitis and pneumonia. Most patients who have the condition need to take antibiotics regularly and schedule frequent check-ups with their doctors to avoid serious complications. In the case of severe IgG deficiency, periodic blood transfusions may be necessary to replenish IgG levels throughout the patient's life.
Several different factors can contribute to an IgG deficiency, but most cases are associated with inherited genetic disorders. X-linked agammaglobulinemia, a condition that primarily affects males, inhibits the development of IgG-creating B cells in the immune system. Genetic conditions tend to be prevalent in infancy or early childhood. A person can also develop IgG deficiency later in life due to protein malnutrition, kidney failure, or cancer. Additionally, long-term use of anticonvulsants and immunosuppressive medications for other conditions has been linked to decreased levels of IgG.
An IgG deficiency itself does not normally cause physical symptoms, but it can leave the body highly vulnerable to frequent viral and bacterial infections. A person with IgG deficiency is likely to experience recurrent respiratory infections that can cause bronchitis, pneumonia, and obstructive lung disease. Chronic sinus infections, the flu, and bacterial-related skin infections are also common with IgG deficiencies. Extremely low levels of IgG can also render vaccines useless, and vaccines can actually trigger the diseases they are designed to prevent.
A doctor usually decides to screen for IgG deficiency and other immune system disorders when a patient is suffering from chronic infections. Blood samples are taken and tested in a hospital laboratory to measure IgG levels. If a patient has severe recurring breathing problems, a CT scan may be done to measure physical damage to the lungs.
Some patients do not need to receive treatment directly directed at their impairments. If IgG levels are moderately low, daily antibiotics and regular visits to the doctor's office may be enough. IgG replacement therapy, which involves transfusions every three to four weeks, may be necessary if levels are very low. Surgery is not effective in improving a deficiency, but a procedure may be necessary if infections have severely damaged lung or sinus tissue. Most patients can control their conditions when they take preventive measures against infections and follow their doctors' orders.