Omalizumab therapy in atopic dermatitis: depletion of IgE does not improve the clinical course - a randomized, placebo-controlled and double blind pilot study.
BACKGROUND
Our understanding of the pathogenic role of IgE in atopic dermatitis is incomplete. We asked whether blocking free IgE would alter the course of the disease.


METHODS
We administered either omalizumab, a humanized monoclonal mouse antibody against IgE, or placebo subcutaneously for 16 weeks to 20 atopic dermatitis patients and measured immunological and clinical disease parameters.


RESULTS
Omalizumab (I) reduced free serum IgE, (II) lowered surface IgE and FcɛRI expression on different peripheral blood mononuclear cells, (III) reduced the saturation of FcɛRI with IgE, (IV) increased the number of free FcɛRI and (V) lowered the number of IgE+, but not of FcɛRI+ cells in skin. The in vivo relevance of these results is evidenced by the increase in the threshold allergen concentration required to give a type I hypersensitivity reaction in the titrated skin test. While not significantly altering the clinical disease parameters, omalizumab treatment led to an improvement of the atopy patch test results in single patients, i.e. an eczematous reaction upon epicutaneous allergen challenge.


CONCLUSIONS
The interference with immediate and delayed type skin tests may imply that a therapeutic benefit of omalizumab treatment, if present at all, would be seen in patients with acute rather than chronic forms of the disease.
Heil
Peter Maximilian
PM
Division of Immunology, Allergy and Infectious Diseases, Department of Dermatology, Medical University of Vienna, Austria. peter.heil@meduniwien.ac.at
Maurer
Dieter
D
Klein
Brigitte
B
Hultsch
Thomas
T
Stingl
Georg
G
D000293:Adolescent; D000328:Adult; D018926:Anti-Allergic Agents / Q000627:therapeutic use; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D003876:Dermatitis, Atopic / Q000188:drug therapy* / Q000276:immunology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D000069444:Omalizumab; D010865:Pilot Projects; D015990:Placebo Effect; D012882:Skin Tests; D016896:Treatment Outcome; D055815:Young Adult
D018926:Anti-Allergic Agents; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000069444:Omalizumab; D007073:Immunoglobulin E