Common Variable Immunodeficiency (CVID)


Fact: CVID is estimated to affect 1 in 25,000 to 1 in 50,000 people worldwide

What is CVID?
Common variable immune deficiency (CVID) is a disorder that impairs the immune system. People with CVID are highly susceptible to infection from foreign invaders such as bacteria, or more rarely, viruses and often develop recurrent infections, particularly in the lungs, sinuses, and ears.

Pneumonia is common in people with CVID. Over time, recurrent infections can lead to chronic lung disease. Affected individuals may also experience infection or inflammation of the gastrointestinaltract, which can cause diarrhea and weight loss.

Abnormal accumulation of immune cells causes enlarged lymph nodes (lymphadenopathy) or an enlarged spleen (splenomegaly) in some people with CVID. Immune cells can accumulate in other organs, forming small lumps called granulomas.

Approximately 25 percent of people with CVID have an autoimmune disorder, which occurs when the immune system malfunctions and attacks the body's tissues and organs. The blood cells are most frequently affected by autoimmune attacks in CVID; the most commonly occurring autoimmune disorders are immune thrombocytopenia purpura, which is an abnormal bleeding disorder caused by a decrease in platelets, and autoimmune hemolytic anemia, which results in premature destruction of red blood cells. Other autoimmune disorders such as rheumatoid arthritis can occur. Individuals with CVID also have a greater than normal risk of developing certain types of cancer, including a cancer of immune system cells called non-Hodgkin lymphoma and less frequently, stomach (gastric) cancer.

People with CVID may start experiencing signs and symptoms of the disorder anytime between childhood and adulthood; most people with CVID are diagnosed in their twenties or thirties. The life expectancy of individuals with CVID varies depending on the severity and frequency of illnesses they experience. Most people with CVID live into adulthood.

There are many different types of CVID that are distinguished by genetic cause. People with the same type of CVID may have varying signs and symptoms.

Affected Populations
CVID equally affects males and females. The prevalence of CVID is approximately 1 in 30,000 people. The diagnosis of CVID is not made in children under the age of 4, because until that time, it may be confused with other genetic defects that must be excluded. In addition, it can be confused with physiologic immaturity. However, most patients have symptoms later and are not diagnosed until ages 20-40.


Symptoms of CVID
Some people with CVID have symptoms as young children, while many others may not develop symptoms until their 20s or 30s—or even later. The most common symptoms are recurring infections involving the ears, sinuses, nose, bronchi (breathing tubes), and lungs (respiratory tract). Severe, repeated infections of the lungs can result in permanent widening and scarring of the bronchi—a chronic condition called bronchiectasis.

People with CVID may also develop enlarged lymph nodes in the neck, chest, or abdomen. The spleen, an organ related to the immune system, may also become enlarged. Lymphocytes may collect in groups inside the intestine known as Peyer’s patches.

Painful swelling of the joints, a condition called polyarthritis, can also develop in people with CVID. The larger joints—knees, ankles, elbows, and wrists—are affected most often.

Gastrointestinal complaints such as abdominal pain, bloating, nausea, vomiting, diarrhea, and weight loss can occur in people with CVID.

People with CVID may have a greater risk of cancer, especially cancers of the lymphoid system and gastrointestinal tract.

Cause
The cause in CVID is unknown in approximately 90 percent of cases. It is likely that this condition is caused by both environmental and genetic factors. While the specific environmental factors are unclear, the genetic influences in CVID are believed to be mutations in genes that are involved in the development and function of immune system cells called B cells. B cells are specialized white blood cells that help protect the body against infection.

When B cells mature, they produce special proteins called antibodies (also known as immunoglobulins). These proteins attach to foreign particles, marking them for destruction. Mutations in the genes associated with CVID result in dysfunctional B cells that cannot make sufficient amounts of antibodies.

Diagnosis of CVID
Doctors suspect CVID when a child or adult has a history of recurrent infections of the ears, sinuses, bronchi, and lungs. The diagnosis is made when a blood test shows low levels of antibodies in the blood, including IgG, IgA, and sometimes IgM. Special lab tests can tell whether B lymphocytes and T lymphocytes are working properly. Another part of the diagnosis of CVID is done by measuring antibody levels in the blood against vaccines such as tetanus, diphtheria, and pneumococcal polysaccharide.

Management
The mainstay of treatment for CVID is immunoglobulin replacement therapy, which reduces arthritic symptoms, infection recurrence, and the severity and/or incidence of the autoimmune disease. Immunoglobulin may be administered intravenously or subcutaneously.

Surgery is required to treat complications of CVID, such as the following:

  • Chronic sinusitis - May require endoscopic sinus surgery
  • Severe autoimmune thrombocytopenia or hemolytic anemia - Can be treated with splenectomy

Want to learn more?

The following are organizations and/or websites dedicated to providing information and education surrounding CVID. These organizations are dedicated to research, education, awareness, and/or support. They are listed in Alphabetical order without any preference or prejudice. Listing these organizations is not a recommendation or referral in any regard for seeking treatment or consultation or support for treatment.

American Academy of Allergy Asthma and Immunology
Immune Deficiency Foundation
Immune Disease.com
Medscape
National Organization for Rare Disorders
U.S. Library of National Medicine

Information on this page taken directly from:
Immune Disease.com
Medscape
National Organization for Rare Disorders
U.S. Library of National Medicine