COMMON VARIABLE IMMUNODEFICIENCY (CVID)
Dr. Ira Shah
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What is

common variable immunodeficiency (CVID)

?

Common variable immunodeficiency (CVID) is a primary Immunodeficiency in which patients have low levels of serum immunoglobulins (antibodies) and an increase susceptibility to infections. In some patients, there is decrease in both IgG and IgA; in others all three antibodies IgG,IgA and IgM may be decreased.

What are the

symptoms of common variable immunodeficiency

?

Symptoms of CVID are varied. Some patients have recurrent infections in childhood. Infections usually involve the ears, sinuses, nose and lungs. Some patients may not develop any symptoms till 2nd or 3rd decade of life. In adults, the presentation may be of an autoimmune disorder such as idiopathic thrombocytopenic purpura (ITP), or arthritis or thyroid disease. Patients may develop enlarged lymph nodes in the neck, chest or abdomen.

What is the

cause of common variable immunodeficiency (CVID)

?

The cause of CVID is largely unknown though it is suspected to be due to abnormality in certain genes.

What is the

treatment of common variable immunodeficiency (CVID)

?

Treatment of CVID consists of replacement of immunoglobulins by giving immunoglobulin (IVIG) replacement therapy. Response is good in patients without significant organ damage. Whenever infection occurs, specific antibiotics for the bacteria causing the infection are given.

What are the

complications of common variable immunodeficiency

?

Complications of CVID depend on the severity of the disease. If there are recurrent severe lung infections, then permanent damage to the lungs can occur and a condition called as bronchiectasis can result. Bronchiectasis can lead to difficulty in breathing, chronic cough and increased risk of infection. Arthritis if untreated can lead to joint deformities, contractures and restricted mobility. Some patients may have malabsorption of nutrients. Patients with CVID are also at high risk of Cancer especially cancer of the gastrointestinal system, skin and lymphoid system.

How is the

diagnosis of common variable immunodeficiency

made?

Diagnosis of CVID is confirmed by finding low levels of IgG, IgA and IgM antibodies in the blood with normal number of B-lymphocytes.

What is

X-linked agammaglobulinemia

?

XLA is a primary immunodeficiency in which patients are unable to produce antibodies (immunoglobulins). As a result, these patients are prone to get recurrent bacterial infections. XLA is also called as Bruton's agammaglobulinemia or congenital agammaglobulinemia.

What are the

symptoms of X-linked agammaglobulinemia

?

Symptoms of XLA are recurrent bacterial infections especially in the ears, sinuses and lungs. They may also get diarrhea, skin infections and serious infections such as septicemia. Common organisms causing infections in these patients are Pneumococcus, Streptococcus, Staphylococcus and Haemophilus influenza.

What is the

cause of X-linked agammaglobulinemia

?

Cause of XLA is a genetic cause. Due to mutations in BTK gene (Bruton's Tyrosine Kinase gene) which is located on X-chromosome, the B-lymphocytes are not formed in patients with XLA. As a result the B-lymphocytes are unable to produce antibodies. Thus, these patients have very small tonsils and lymph nodes as bulk of tonsils and lymph nodes is formed of B-lymphocytes which are absent in these patients. Since the genetic defect is present on the X-chromosome, XLA is seen in boys only.

How is the

diagnosis of X-linked agammaglobulinemia

made?

Diagnosis of XLA is established by demonstrating decreased IgG, IgA, & IgM immunoglobulins in the blood along with low number of B-lymphocytes. Diagnosis of XLA is confirmed by demonstrating absence of BTK protein in monocytes or platelets or by detection of mutation in BTK gene by genetic tests.

What is the

treatment of X-linked agammaglobulinemia

?

Treatment of XLA consists of immunoglobulin replacement therapy.. Patients with XLA should not receive live vaccines such as oral polio vaccine, MMR vaccine.

What is the

inheritance of X-linked agammaglobulinemia

?

Inheritance of XLA is due to defect on X-chromosome. Females have no disease but may be carriers of the defective gene. A brother of the affected boy with XLA has 50% chance of having the disease whereas the sisters may be carriers or have no gene defect. If the father is suffering from XLA, then his daughters will be carriers of the defective gene whereas the sons will be normal. Currently these genetic tests are being performed only in few laboratories.

What is the life expectation of patients with X-linked agammaglobulinemia?
Most XLA patients who receive immunoglobulins will be able to lead relatively normal life.



Contributor Information and Disclosures

Dr. Ira Shah
Consultant Pediatrician, Nanavati Hospital and B.J.Wadia Hospital for Children, Mumbai India.


First Created : 1/4/2001

References

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