Probable

Male or female patient who has a marked decrease (at least 2 SD below the mean for age) in two out of three of the major isotypes (IgM, IgG and IgA) and fulfills all of the following criteria:

1. Onset of immunodeficiency at greater than 2 years of age
2. Absent isohemagglutinins and/or poor response to vaccines
3. Defined causes of hypogammaglobulinemia have been excluded (see Table)

Possible

Male or female patient who has a marked decrease (more than 2 SD below the mean for age) in one of the major isotypes (IgM, IgG and IgA) and fulfills all of the following criteria:

1. Onset of immunodeficiency at greater than 2 years of age
2. Absent isohemagglutinins and/or poor response to vaccines
3. Defined causes of hypogammaglobulinemia have been excluded (see Table)

Spectrum of disease

Most patients with CVI are recognized to have immunodeficiency in the second, third or fourth decade of life, after they have had several pneumonias; however children and older adults may be affected. Viral, fungal and parasitic infections as well as bacterial infections may be problematic. The serum concentration of IgM is normal in about half of the patients. Abnormalities in T cell numbers or function are common. The majority of patients have normal numbers of B cells; however, some have low or absent B cells. Approximately 50% of patients have autoimmune manifestations. There is an increased risk of malignancy.

Further information

• Patient and Family Handbook For The Primary Immune Deficiency Diseases by IDF.
• Common Variable Immunodeficiency by The Jeffrey Modell Foundation (JMF).