It is characterized by low levels of antibodies in the blood stream and an increased susceptibility to infections. Both male and female are equally affected with this problem in the third or fourth decade of life.

Patients with CVID develop recurrent infections of the sinuses, ears, nose lungs and gastrointestinal tract. They may also develop enlarged lymph nodes or an enlarged spleen.

Individuals with CVID have an increased incidence of malignant lymphomas and autoimmune disorders such as lupus, rheumatoid arthritis, inflammatory bowel disease and autoimmune hemolytic anemia.

The cause of this problem is not known but certain infections with viruses are suspected to be the culprits in causing this disease. Genetic factors do play a part in the development of common variable immunodeficiency. However, there is no single gene mutation that can be identified.