Infectious Disease

Other Immunodeficiencies

Woman going under for surgery

HIV or the human immunodeficiency virus is the best-known illness that attacks the body's immune system. Other conditions exist as well, however, that undermine a person's ability to fight off opportunistic infections. Some of these are inherited or genetic conditions and are known collectively as primary immunodeficiency diseases. Some of these conditions are secondary immunodeficiencies, which are acquired by taking immune-suppressing drugs. Still, others are specific diseases like diabetes and certain blood disorders.

Primary Immunodeficiency Diseases

The World Health Organization classifies more than 300 genetic disorders as primary immunodeficiency diseases, three of which are profiled below. Each disorder has its own specific mechanism.

Common Variable Immune Deficiency (CVID)

Common Variable Immune Deficiency is believed to affect one out of every 25,000 people. Research suggests that a recessive autosomal gene causes it.

CVID's presentation varies widely, but in every case, signs and symptoms can be traced to issues with immunoglobulins and T-cells. Although CVID frequently remains undiagnosed until early middle age, affected individuals typically have a history of recurrent bacterial infections involving the ears, nasal sinuses, and lungs. They may also suffer from anemia and clotting disorders, and malabsorption and other gastrointestinal complaints. Treatment usually involves immunoglobulin replacement therapy as well as interventions tailored to specific symptoms.

Wiskott-Aldrich syndrome (WAS)

Wiskott-Aldrich syndrome is an X-linked recessive condition caused by the underproduction of a protein called WASp. The syndrome appears in less than one out of every 100,000 people and mostly affects males.

The syndrome has a variable expression depending upon the amount of WASp the body is still able to produce, but presentation typically involves abnormal bleeding as well as an enhanced susceptibility to infections. Eczema and other autoimmune symptoms are common, and WAS patients have an enhanced risk of developing cancer. Prophylactic treatment with intravenous immunoglobulin is often indicated. Bone marrow transplants stem cell transplants, and splenectomies have also been used to manage symptoms.

Chronic Granulomatous Disease (CGD)

Chronic Granulomatous Disease occurs in approximately one out of every 250,000 births. The most common form of CGD is associated with an X-linked genetic defect that only affects males, but the condition is also associated with recessive genes on other chromosomes that can affect both males and females.

People with CGD have immune systems that are normal in all respects but one: Their phagocytes do not produce the hydrogen peroxide and other chemicals necessary to kill Staphylococcus aureus, Burkholderia cepacia complex, Serratia marcescens, Nocardia and Aspergillus. Consequently, these people frequently develop infections from these bacteria that can make them very seriously ill. Patients with CGD are prone to excessive inflammation even in the absence of infection, and chronic inflammation leads to the development of granulomas. Treatment involves aggressive prophylaxis with antibiotics and antifungal agents as well as interferon injections.

Secondary Immunodeficiencies

Secondary immunodeficiency disorders are commonly associated with the use of certain drugs. Synthetic glucocorticoids are the most common of these medications.

When corticosteroids such as dexamethasone and prednisone are administered to help prevent the rejection of a transplanted organ, immunosuppression is the desired result. However, when corticosteroids are prescribed to control inflammation in rheumatoid arthritis, lupus, Crohn's disease, asthma, or allergies, immunosuppression can become a harmful side effect.

Corticosteroids not only increase your susceptibility to infection, they can also prevent you from exhibiting the symptoms of an infection until that infection is far advanced. People who are taking corticosteroids should wash their hands frequently and avoid being around people with chicken pox, measles or other infectious diseases.

Diseases and Blood Disorders

Without effective treatment, diabetes can cause significant immune system malfunctions. When blood sugar levels are elevated, glucose binds selectively to the surfaces of immune system cells, which inhibits their ability to respond to legitimate threats. Elevated blood sugar levels also provide a favorable medium for bacterial growth. People with diabetes have a much greater risk of becoming infected with bacteria like Salmonella, Listeria monocytogenes, and Campylobacter jejuni than do members of the general population.

Blood disorders such as aplastic anemia, leukemia, multiple myelomas, and sickle cell disease are also associated with chronic immunodeficiency.

Aplastic Anemia

Aplastic anemia affects the ability of the stem cells in bone marrow to produce sufficient quantities of blood cells. White blood cells essential to healthy immune response can be affected as well red blood cells. Aplastic anemia can be an inherited condition, or it can be the sequelae to certain viral infections or the use of certain medications or chemotherapies.

Leukemia

Leukemia is a type of cancer that involves the abnormal production of the white blood cells that are the primary agents of the body's immune response. In the absence of those white blood cells, the body is unable to fight infections adequately.

Multiple Myeloma

Multiple myeloma is a type of cancer that causes the abnormal proliferation of a specific type of white blood cell called the plasma cell. Impaired plasma cells release excess amounts of abnormal antibodies that are ineffective at fighting infections and that can cause significant organ and bone damage.

Sickle Cell Disease

Sickle cell disease is a genetic disorder characterized by structurally abnormal hemoglobin, which results in red blood cells with a concave shape that can easily become stuck in blood vessels. The spleen is one of the organs that are most susceptible to damage from these abnormal red blood cells. When the spleen is damaged, it can no longer filter out bacteria or produce the white blood cells that fight infections.