IgG subclass deficiency
also see B-cell defects

• May have deficiencies of 1 or more subclasses despite normal or elevated total IgG levels
  • IgG1 and IgG3 -> protein antigens
  • IgG2 -> polysaccharide antigens
• Presentation: Variable; IgG2 deficiency: Hib infection after vaccination. Recurrent bacterial infections, sinusitis and bronchopulmonary disease
• Labs: Total IgG levels normal; need to check subclasses
• Treatment: Usually none; Treat infections ; IVIG if very severe
• Prognosis: in most cases, a self-limited condition that resolves by 4-5 years of age

CHLA Board review 2005