A placebo-controlled trial of immunotherapy with two extracts of Dermatophagoides pteronyssinus in allergic rhinitis, comparing clinical outcome with changes in antigen-specific IgE, IgG, and IgG subclasses.
A double-blind, placebo-controlled trial of immunotherapy was conducted in patients with Dermatophagoides pteronyssinus rhinitis. Thirty patients received an extract with a high content of Der p I (Pharmalgen), 20 received a conventional mite extract (Allpyral), and 30 patients received histamine chloride (placebo). Specific IgG and subclasses were measured before and after 3 and 12 months of treatment by RIA and/or ELISA, and specific IgE by RAST. Clinical outcome was assessed by skin prick tests, nasal challenge, visual analogue, and diary-card symptom and drug scores; from these findings, a clinical index was derived. An IgG response occurred only in the Pharmalgen-treated group: D. pter IgG and IgG1 increased by 3 months (p less than 0.05) and then plateaued to 12 months (p less than 0.05). IgG4 levels increased throughout treatment (p less than 0.05 and p less than 0.01), as did the IgG/IgE ratio. A subclass switch from IgG1 to IgG4 occurred. D. pter IgE rose at 3 months (p less than 0.05). Clinical improvement occurred at 3 and 12 months in the Pharmalgen-treated group only. Pretreatment levels of IgE, IgG1, or IgG4 did not predict clinical outcome. Our findings are compatible with the hypothesis that IgG subclasses may modulate antigen-IgE interactions, although the antibody response to this potent extract need not be causally related to improvement.
Molecular Immunopathology Unit, University of Cambridge Clinical School, England.
S M
SM
McHugh
B
B
Lavelle
D M
DM
Kemeny
S
S
Patel
P W
PW
Ewan
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000627:therapeutic use; D000818:Animals; D000941:Antigens / Q000276:immunology / Q000627:therapeutic use*; D039741:Antigens, Dermatophagoides; D003888:Desensitization, Immunologic / Q000379:methods; D004311:Double-Blind Method; D000939:Epitopes / Q000032:analysis* / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis* / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007167:Immunotherapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology*; D010919:Placebos; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology / Q000628:therapy*; D013997:Time Factors
D000485:Allergens; D000941:Antigens; D039741:Antigens, Dermatophagoides; D000939:Epitopes; D007074:Immunoglobulin G; D010919:Placebos; D007073:Immunoglobulin E