Common Variable Immunodeficiency, which is also abbreviated as CVID, is a type of health disorder that can affect a number of systems in the body. This condition appears when a person’s body lacks immunoglobulins or antibodies.
When the number of antibodies is reduced, a person is more susceptible to infections because the body is unable to fight off attacking microorganisms. Researchers who have studied this condition believe some instances of CVID may be inherited and that a common unhealthy gene is passed on from one generation to the next. This condition is prevalent in both men and women.
The first symptoms of common variable immunodeficiency, which are uncommon infections that are recurrent, often begin in children or teenagers, but the condition is not usually diagnosed until the individual reaches adulthood.
People who have CVID will have frequent bacterial infections that have a negative impact on the lungs, ears and sinuses.
Issues with the gastrointestinal system are another common symptom and this can lead to vomiting, diarrhea, stomach bloating and pain, and losing weight. Autoimmune disorders, such as vitiligo, rheumatoid arthritis and hemolytic anemia are also prevalent in many individuals who have CVID.
While the overall cause of common variable immunodeficiency (CVID) is unknown in the majority of patients with this condition, approximately 10% of those diagnosed have a genetic mutation as the driver. For those with genetically-mediated common variable immunodeficiency, causes can either be autosomal dominant or autosomal recessive genetic disorders. Autosomal dominant genetic conditions only require one set of genes to be present for the disease to manifest. Autosomal recessive conditions require two copies, one from both parents.
Additionally, so far, mutations in anywhere from 5 to 13 different genes have been identified as drivers for common variable immunodeficiency. Regarding the drivers in genetically related cases of CVID, the function of B cells (specialized white blood cells that produce immunoglobulins), is the cause. In some instances, impairment of the T cell system, which can also drive B cell defect, can cause CVID.
In cases where a genetic component may or may not be identified, the presence of an autoimmune disorder appears to be a risk factor in the development of CVID; up to 25% of those diagnosed have an autoimmune disorder, with the most common disorders being thrombocytopenia purpura and rheumatoid arthritis.
Individuals who are diagnosed with common variable immunodeficiency often receive immunoglobulin therapy, also called IG replacement therapy, which prevents the succession of infections. An antibody, called cyclosporin A, is also frequently used to treat people who have CVID. Some physicians may recommend antimicrobial therapy during the first phase of an infection.
Immunosuppressive medications or steroids may be prescribed for patients who have a disease of the autoimmune system. The type of treatment also depends on the body system that is affected by the disease.
Given the largely unknown drivers of the development of common variable immunodeficiency outside of the 10% of genetically mediated cases, recommendations for prevention are not robust.
In instances of suspected CVID, it is important that genetic testing be performed for proper diagnosis. For families where individuals have a history of CVID, monitoring and potential genetic testing could be helpful, especially in instances of autosomal dominant CVID.
For CVID that may not be caused by genetic factors, identification of autoimmune disorders may be helpful, given the identified correlation in 25% of cases. Monitoring of the autoimmune disorders, and genetic testing should there be signs and symptoms of CVID, could prove to be helpful.