Background: This study reports the clinical and immunological state of patients 3 years after a 6-year period of Xolair treatment for severe allergic asthma.
Methods: The patient’s cat allergen sensitivity, measured as CD-sens, IgE and IgE- and IgG4 antibodies, was analysed and compared with asthma severity evaluated from FEV1 and a questionnaire.
Results: Three years after treatment with Xolair was stopped, 12/18 patients reported improved or unchanged asthma compared with ongoing Xolair treatment. Most of the patients were in a stable clinical condition, 16/18 had not increased nightly asthma attacks and 14/18 little or no increase in medication. The CD-sens to cat was still significantly lower (P < 0.02) than untreated patients with allergic asthma and lower than expected from their serum IgE antibody levels.
Conclusion: Most of the patients in this study had, still 3 years after closing of 6 years Xolair treatment, a surprisingly mild and stable asthma. Interestingly, the observed, considerable, downregulation of basophil allergen sensitivity, CD-sens, most likely representing mast cell allergen sensitivity, contributed to the clinical results.