Common Variable Immunodeficiency
Common Variable Immunodeficiency (CVID) is the most frequently diagnosed primary immunodeficiency disease, where a part of the immune system is absent or dysfunctional. In people with CVID, the B cells are affected. B cells are a specialised white blood cell in the immune system that protects the body from infection. When B cells mature, they produce proteins called antibodies (or immunoglobulins). These antibodies can recognise patterns on foreign particles (eg viruses) and form an important part of the immune response. CVID is characterised by dysfunctional B cells that cannot make sufficient amounts of certain immunoglobulins/antibodies (namely IgG, IgA and IgM). The extent of the deficiency and the immunoglobulins involved varies between patients from low (hypogammaglobulinemia) to completely absent (agammaglobulinemia), hence the term “variable”. This increases a person’s susceptibility to infection, in particular respiratory-related illnesses as well as tumours. Around 20-25% of those with CVID subsequently develop an autoimmune disease.
Who is affected?
It is found in about 1 in 25,000 people and affects both males and females equally. About 20% of patients are diagnosed in childhood, although the majority are diagnosed between 20-40 years of age.
Signs and Symptoms
The main signs and symptoms are recurrent infections involving the ears, nasal sinuses and lungs, which can appear anytime from childhood through to adulthood. Repeated and severe respiratory infections can lead to bronchiectasis, which is permanent scarring of the airways of the lung. CVID can also be complicated by the detection of inflammatory lesions (granulomas) in the lung that are identical to those observed in sarcoidosis.
Diagnosis can be made using blood tests that measure the level of antibodies and B cells in the blood and through the exclusion of other immunodeficiency diseases. The functionality of serum antibodies is measured by testing against vaccine antigens such as tetanus or diphtheria, measles, mumps, or rubella. People with CVID the antibody response to vaccination is usually poor.
Standard management for CVID in patients without organ damage involve immunoglobulin replacement therapy with plasma products derived from healthy donors, which usually alleviates symptoms. They will require these treatments regularly for the remainder of their lives.
CVID patients which chronic respiratory infections can be treated with broad-spectrum antibiotics to fight the infection.
There is no cure.
The China-Australia Centre for Personalised Immunology is investigating the cause of this immunodeficiency, to improve treatment and to help to find a cure for this little known disease.
Information on this page is not intended to replace medical advice and any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner.