Common variable immunodeficiency

Common Variable Immunodeficiency (CVID) is an immune disorder characterized by recurrent infections and low antibody levels, specifically in immunoglobulin (Ig) types IgG, IgM and IgA. It is thought to affect between 1 in 25,000 to 1 in 50,000 people worldwide. CVID is a rare primary immunodeficiency, and can take many forms due to the diverse ways in which antibody production can be impaired. Generally, CVID symptoms include high susceptibility to foreign invaders, chronic lung disease, and inflammation and infection of the gastrointestinal tract. However, symptoms vary greatly. The disease is not only phenotypically heterogeneous, but also hard to diagnose, taking on average 6–7 years after onset.