Changes in serum immunoglobulin patterns in adults with common variable immunodeficiency.

Striking variations of serum immunoglobulin class and IgG subclass levels were observed in five patients with common variable immunodeficiency. They occurred mainly in untreated patients or, in those patients who received substitutive therapy, could not be merely due to replacement. They result in major changes in the immunoglobulin deficiency patterns, such as a shift from profound hypoimmunoglobulinaemia to IgA/IgG2/IgG4 deficiency or to isolated IgG2 deficiency. These findings have practical implications for the diagnosis and management of patients with primary humoral immunodeficiency.