Common variable immunodeficiency Acquired hypogammaglobulinemia

• History / PE:
  Very similar in presentation to Bruton's, but less severe
  No sexual predominance
  Manifests later in life (15-35 years old)
  
• Diagnosis:
  Serum concentrations of antibodies are low, however NO marked decrease in the number of circulating B cells
• Differential Diagnosis:
  Bruton's agammaglobulinemia (inherited, absent/low B cells)