Primary Immunodeficiency Diseases
The human immune system protects the body like the Army, Navy, Air Force and Marines protect our country.
Troops of white blood cells and antibodies travel through our bloodstream and lymph nodes, defending against attacks by foreign invaders such as bacteria, viruses and fungi. Like our defense department, they are an interrelated system designed to defend from all sides. When one fails, we are open to infection.
The first clue might be recurrent pneumonia – or difficult-to-treat sinus, ear, skin or gastrointestinal infections. But the problem could lie deeper than the site of the infection.
A pattern of severe, repeat infections could point to a Primary Immunodeficiency Disease, or PIDD.
Allergy & Asthma Today recently interviewed allergist Prem Menon, MD, of the Asthma, Allergy and Immunology Center in Baton Rouge, La., about PIDD diagnosis and treatment. Dr. Menon is a long-time member of the Board of Directors with Allergy & Asthma Network and past president of the Louisiana Society of Allergy, Asthma and Immunology. As an expert in PIDDs, he wants to raise awareness of these diseases to help families get medical help more quickly.
Allergy & Asthma Today: How common are PIDDs?
There are 180 PIDDs identified that affect about 1 in 2,000 people in the United States. Most cases are inherited, passed down from one or both parents. Some are potentially life-threatening.
In recent years, there has been a dramatic increase in recognized PIDDs, so it’s not as rare as once thought. B-cell deficiency, in which the body produces too few protective B-cells or antibodies, is the most common, making up 60 percent of all cases.
Severe combined immunodeficiency (SCID), like the famous “bubble baby” had, is rare and affects 1 in 50,000 people.
AAT: What are common PIDD symptoms?
Dr. Menon: Symptoms differ depending on the individual. In general, they include frequent and recurrent bouts of pneumonia, bronchitis, sinus or ear infections, meningitis, skin infections or blood infections.
Other problems may include inflammation and infection of internal organs; blood disorders such as anemia; digestive problems such as nausea or diarrhea; delayed growth; malabsorption of food; and autoimmune disorders such as lupus, or rheumatoid arthritis.
AAT: Is it possible some people have PIDD and don’t know it?
Dr. Menon: Yes, that is common. Some cases of PIDD are mild and may go unnoticed for years; others are severe enough to be discovered at birth.
There is a movement to screen all newborns with the TREC (T-cell receptor excision circle) assay. This identifies infants with most forms of SCID or with very low T-lymphocytes due to other conditions.
AAT: Why is diagnosis sometimes delayed?
Dr. Menon: Quite often, patients initially seek treatment from their primary care physicians. They may also seek treatment from specialists like ENTs (ear, nose and throat doctors, or otolaryngologists) or pulmonologists. The conventional wisdom is to treat the symptoms with multiple courses of antibiotics or surgery when the infection continues or recurs. They usually do not run tests that lead to the diagnosis of PIDD. That is the reason for the missed diagnosis. It can take years of trial and error before the patient gets referred to an immunologist.
That’s unfortunate, because early diagnosis and treatment of PIDD can slow the progression of the disease and prevent infections that can cause long-term problems.
Raising awareness among healthcare providers, caregivers, pharmacists and the general public can help patients with PIDD and their families find support sooner.
AAT: When should a patient ask their primary care doctor for a referral to an immunologist?
Dr. Menon: If you or your child experience frequent, recurrent or severe infections, or infections that don’t respond to antibiotic treatment, request a referral to an immunologist who can diagnose PIDD.
AAT: How should a patient prepare for a PIDD appointment with an immunologist?
Dr. Menon: Bring a detailed medical and surgical history, including laboratory test results, x-rays or CT scans, a list of all medications, history of doctors visits, and details of any sinus or ear surgery. If possible, bring copies of hospital records and a print-out of prescriptions from the pharmacy.
It is also important to detail your family’s health history. Specifically include any early death of a family member or death due to an unexplained illness.
In addition to providing information, you’ll want to ask your own questions:
- What is the most likely cause of my symptoms?
- What tests are needed to confirm the diagnosis?
- What treatments are available, and which do you recommend? Are there any alternatives to treatment?
- What side effects might I experience from treatment?
- Are there any activity restrictions related to treatment?
AAT: What are common PIDD treatment options?
Dr. Menon: Treatment involves preventing and treating infections, boosting the immune system, and treating the underlying cause. In some cases, PIDDs are linked to serious illnesses such as autoimmune disorders or cancer, which also require treatment.
Patients and their physicians should consider the use of preventive antibiotics. Infections should be treated promptly and aggressively. If infections don’t respond, hospitalization and intravenous (IV) antibiotics may be necessary. Some patients may need long-term antibiotics to help prevent infections and damage to lungs or ears.
In addition, patients may need mucus thinners, cough syrup or decongestants to help relieve symptoms caused by infections. I encourage patients to take probiotics, especially when they are on antibiotics, to reduce the risk of colitis.
PIDD patients can boost their immune system with therapies designed to fight bacterial and viral infections by antibody replacement. The two common examples are intravenous (IV) or subcutaneous (SC) immunoglobulin infusions and gamma interferon therapy.
Another option for some is stem cell transplantation, which offers a permanent cure for several forms of PIDD. With this treatment, healthy stem cells are transferred to the person with immunodeficiency, giving them a normally functioning immune system.
AAT: What are some other ways patients can strengthen their immune system and prevent respiratory infections?
Dr. Menon: Since most PIDDs are genetic-based, there’s no way to prevent them. However, you and your family can take steps to prevent infections by practicing good hygiene, including handwashing and taking care of your teeth, eating a healthy, balanced diet, keeping away from people with colds or the flu, getting proper vaccinations and taking any medications as needed.
PIDD, Allergies and Asthma
Allergies are characterized by an abundance of immune system IgE antibodies that react to usually harmless substances like pollen, dust mites or pet dander. IgE binds to mast cells and releases histamine, which cause allergy symptoms.
Complications of allergies, such as sinus congestion or infection, can be confused with PIDD infections; asthma can be exacerbated by PIDD respiratory infections. The interrelation between allergic diseases and primary immunodeficiency point up the importance of treatment by an allergist/immunologist trained to understand both conditions.
PIDDs vs. Autoimmune Diseases
Primary immunodeficiency diseases involve abnormalities in specific components of the immune system that lead to an increased susceptibility to infection. Autoimmunity is a form of immune dysregulation in which the immune response is directed against normal parts of the body such as cells, tissues or organs.
- Immune Deficiency Foundation: www.primaryimmune.org
- Jeffrey Modell Foundation: www.jmfworld.org/jmfworld.org
- American Academy of Allergy, Asthma & Immunology (AAAAI): www.aaaai.org
- American College of Allergy, Asthma & Immunology (ACAAI): www.acaai.org
The Immune Deficiency Foundation, AAAAI and ACAAI web sites include tools to help you locate physicians who specialize in PIDD.