Dermatophagoides farinae

The complete mechanisms of allergen immunotherapy are not clear and remain the subject of investigation. The allergic reaction is dependent on the presence of allergen-specific immunoglobulin E (IgE) antibodies that are bound to specific receptors on mast cells and basophils. The presence of IgE antibodies sensitizes these cells, and upon interaction with the appropriate allergens, histamine and other mediators are released which produce local or systemic responses in sensitive individuals, and characteristic symptoms of atopic diseases, such as allergic rhinitis and allergic asthma. Changes in serum antibody and T-lymphocyte responses resulting from immunotherapy have been demonstrated, and these changes often correlate closely with clinical (symptom) improvements. Specific mechanisms may vary depending on the nature of the allergic disease, the allergenic specificities of patients and populations, extract formulations, route of administration, dose and duration of treatment. Subcutaneous administration of allergenic extracts is known to elicit numerous immunological changes that are both time and dose-dependent. Many of these changes appear to be related to (or a precursor to) improvements in symptoms and other clinical parameters, as noted above. Specific changes found after immunotherapy with dust mite extracts include significant increases in mite-specific IgG4 antibodies, interleukin-10-positive T cells, and several T-cell receptors, and significant decreases in serum nitric oxide, eosinophil catonic protein, interleukin-4-positive T cells and IgE-mediated basophil histamine release.