IgG subclass deficiency

Epidemiology

• often diagnosed in adults

Clinical manifestations

• recurrent bacterial & viral infections, especially respiratory tract
  • encapsulated bacteria, Mycoplasma, respiratory viruses
• recurrent diarrhea due to giardiasis or Norovirus infection

Laboratory

• serum IgG subclasses (will not change management
• assessment of response to immunization with polysaccharide & protein antigens
  • tetanus toxoid or diphtheria & tetanus toxoid (dT)
  • Haemophilus influenzae B conjugate
  • Pneumovax
  • collect serum before immunization & 2-3 weeks after
  • assess antibody content

Complications

• autoimmune disease
  • inflammatory bowel disease
  • granulomatous disease
  • bronchietasis
  • malignancies

Management

• intravenous immune globulin decreases risk of infection

More general terms

• humoral immune dysfunction