The immune system is made up of organs, cells, and proteins that help defend and protect the body from foreign invaders such as allergens, cancer cells, and especially pathogens (viruses, bacteria, fungi, and parasites that cause disease). Immune system organs such as the spleen, thymus, tonsils, adenoids, and bone marrow produce white blood cells and antibodies that fight or destroy pathogens or abnormal cells. In immunodeficiency diseases or disorders, the body is unable to effectively fight foreign invaders, resulting in frequent, unusual, and/or difficult-to-treat infections.
Immunodeficiency disorders can be primary, a genetic disorder usually present at birth (ex. Severe Combined Immunodeficiency (SCID), Autoimmune Lymphoproliferative Syndrome (ALPS), Common Variable Immunodeficiency (CVID), and Chronic Granulomatous Disease (CGD), Immunodeficiency (SCID). There are over 200 known primary immunodeficiency disorders (PIDD). Immunodeficiency disorders can also be secondary, developing due to another medical condition or taking medications that affect the immune system. One of the most common causes of immunodeficiency disease in South Africa is HIV, which causes AIDS (acquired immunodeficiency syndrome.)
In many cases of secondary immunodeficiency diseases, the immunodeficiency may resolve on its own with no treatment, or after the medication is stopped or the underlying disease process is controlled. However, in the case of AIDs, and in PIDD, medication treatment is usually required. In severe cases, stem cell transplantation, gene therapy, or even thymus tissue transplant may be used.
Treatment with medications for immunodeficiency disorders is intended to help prevent infections, treat infections, and replace immune system components. The treatment type depends on the type of immunodeficiency disorder, particularly which component of the immune system is deficient.
Antibacterial Medications aka “antibiotics” are given to treat bacterial infections, as well as to prevent them. In patients with an immunodeficiency disorder, antibiotics may be used at the first sign of infection, such as a fever. They will also be prescribed before surgeries or dental procedures, which can increase the risk of bacteria entering the body. In some cases, when an immunodeficiency disorder significantly increases the risk of bacterial infections (ex. SCID), antibiotics may also be given long-term to prevent them. Many different antibacterial medications are available to treat and prevent bacterial infection. Some commonly used medications include amoxicillin, penicillin, cephalexin, levofloxacin, sulfamethoxazole/trimethoprim, clarithromycin, and azithromycin.
Antiviral Medications are given at the first sign of infection in patients with immunodeficiency disorders that increase the risk of viral infection (ex. immunodeficiency due to T-cell abnormalities) and are also given for prevention of viral infections. Examples of antivirals used for treatment and prevention in immunodeficiency disorders include acyclovir, oseltamivir, zanamivir for influenza, entecavir, and lamivudine.
Antifungal Medications are used to prevent and treat fungal infections in patients with immunodeficiency disorders. Examples of antifungals used include fluconazole, voriconazole, and micafungin.
*Dosing regimens for antibiotics, antivirals, and antifungals are often different (less frequent) for the prevention of infection than for the treatment of known or suspected infections. Patients with immunodeficiency disease also usually require longer courses of medications for infection treatment.
Immune Globulin (also called “gamma globulin,” “IVIG,” or “SCIG”) is the liquid component in blood that contains antibodies (aka “immunoglobulins”). Administering this medication can replace the vital immune system proteins called antibodies (aka “immunoglobulins”), in patients with immunodeficiency diseases that impair the body’s ability to produce antibodies, which accounts for more than half of all PIDD. These are given by subcutaneous (under the skin) or IV infusion, once weekly to once monthly. Immune globulin treatment is intended to help prevent infection by providing antibodies to fight potential pathogens.
Common side effects of anti-infective drugs include nausea, vomiting, diarrhoea, headache, drowsiness, and dizziness. Serious side effects include allergic reactions and the development of secondary infections (killing “good” bacteria in the body can increase the growth of “bad” bacteria and other pathogens). Examples include yeast infections and Clostridium difficile (C. diff) infections. These can be particularly problematic in patients with immunodeficiency disorders. If you experience severe and/or bloody diarrhoea, rash, or itching while taking antibiotics, contact your doctor right away.
Side effects of immune globulin therapy are usually infusion related. These include nausea, vomiting, fever, chills, body aches, wheezing, and chest tightness. Infusion-related reactions can usually be decreased or eliminated by slowing the rate of infusion or giving medications that treat symptoms prior to administration. Rare, but serious, side effects of immune globulin include aseptic (not germ-related) meningitis, blood clots, kidney failure, and anaphylaxis (severe allergic reaction). These are not usually related to infusion rate and may occur up to 72 hours after receiving the medication. If you experience severe headache, decreased urination, severe leg or arm pain, shortness of breath, or a combination of rash/hives, shortness of breath, or nausea/vomiting after immune globulin infusion, seek medical attention right away.
Vaccines are an important part of treating patients with immunodeficiency disorders because they help protect them from many life-threatening infectious diseases. Vaccines work by stimulating the body to produce antibodies to specific bacteria and viruses. So, they are only effective in patients whose specific immunodeficiency disease does not affect antibody production. Some vaccines are considered “live” vaccines and inject a small amount of live bacteria or virus into the body to produce an immune response. These may not be appropriate for individuals with specific types of immunodeficiency (ex. T-cell or B-cell abnormalities) because they can cause infection from the small amount of live pathogen injected with the vaccine. It is important to talk to your doctor about whether you should receive vaccines, and which ones are appropriate for you.
It is important that anyone with any type of immunodeficiency disease takes other precautions to decrease infection risk. These include proper and frequent hand hygiene, masking in public when respiratory viruses such as flu and COVID-19 are widespread, avoiding contact with people with known infections, not drinking possibly contaminated water, and not eating undercooked foods. Medication treatment cannot replace these measures, but it can help prevent infections and treat them when they occur.