B Cell Deficiency

Humoral immunodeficiency disorders are characterized by B cell abnormalities which can lead to a decrease in the level and/or function of B cells and antibodies. Patients with humoral immunodeficiencies generally present with recurrent bacterial sinopulmonary or gastrointestinal infections and have a propensity for autoimmune diseases. Certain B cell deficiencies are associated with comorbidities such as bronchiectasis and chronic lung disease. Management of humoral deficiencies includes treating infections aggressively, immunoglobulin replacement therapy, and addressing complications including chronic lung disease, autoimmune disease, and malignancy. In this chapter, we will use case-based discussion to review common humoral immunodeficiencies, such as X- linked Agammaglobulinemia (XLA) and Common Variable Immunodeficiency (CVID), including their pathophysiology, clinical manifestation, diagnosis, treatment, and prognosis.