Allergens
  • Allergic asthma-- dependent on:
    •  T and B lymphocytes IgE responses
    •  activated by antigen interaction with mast-cell bound IgE molecules
  • Most asthma-producing allergens: airborne, abundant
  • Following sensitization, very small amounts of allergen can produce significant worsening of asthma
  • Immune mechanisms:
    • causal basis: 25% to 35%
  • Allergic asthma:
    • frequently seasonal
    • observed mostly in young adults and children
    • nonseasonal: -- allergy due to:
      •  dust mites
      •  molds
      •  animal danders
      •  feathers
      •  antigens continuously present
    • Immediate response to antigenic exposure: airway obstruction develops in minutes, then dissipates
      • in 30% to 50% of asthmatics, a second wave of bronchoconstriction (late reaction) develops 6-10 hours later
  • Possible mechanism by which inhaled allergen® initiates acute asthmatic episode:
    1. very small antigenic particles penetrate lung's defenses
    2. antigen contacts mast cells that interdigitate with luminal surface epithelial cells in the central airway.
McFadden, Jr., E. R., Diseases of the Respiratory System: Asthma, In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp 1419-1426.
Way, W.L., Fields, H.L. and Way, E. L. Opioid Analgesics and Antagonists, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 496-515.