Common variable immunodeficiency (CVID) is a primary immunodeficiency due to selected genetic defects. This syndrome is frequently associated with non-infectious complications such as interstitial lung disease, enteropathy, autoimmunity and malignancies, with lack of isotype-switched B cells. B cell–activating factor (BAFF) is one of the TNF family members important for IgA class switching and plasma cell survival. Excessive levels of BAFF are found in CVID patients.
