Basophil allergen threshold sensitivity: a useful approach to anti-IgE treatment efficacy evaluation.
BACKGROUND
Monitoring of the allergen sensitivity of a patient is most important for optimal patient care and a basic prerequisite for immunomodulating treatment. The objective of this study was to investigate how basophil allergen sensitivity can be applied in the monitoring of anti-immunoglobulin E (IgE) treatment.


METHODS
Basophils from timothy grass pollen allergic patients were, by flow cytometry, analysed for allergen threshold sensitivity (CD-sens) by measuring CD63 up-regulation on CD203c-identified basophils. The results were compared with maximal percentage CD63 up-regulation at one allergen dose (CD-max), skin prick test end-point allergen titration, (SPT-sens), nasal provocation titration tests (nasal provocation titre) and serum IgE and IgE antibody concentrations.


RESULTS
There was a significant correlation (r = 0.50, P = 0.01) between CD-sens and SPT-sens, CD-sens and the IgE antibody concentration in percentage of 'total IgE' (relative IgE antibody concentration) (r = 0.72, P < 0.001) as well as between CD-sens and nasal provocation titre (r = 0.54, P < 0.05) but, in contrast, CD-max did not correlate with any of the sensitization parameters, i.e. SPT-sens, nasal provocation titre, absolute and relative IgE antibody concentration or CD-sens. CD-sens could be used to monitor omalizumab treatment efficacy while, based on CD-max, four of seven symptom-free patients on omalizumab would have been classified as having ongoing allergy.


CONCLUSIONS
CD-sens seems to be very useful for the determination of a patient's allergen sensitivity and should be evaluated for the measurement and monitoring of anti-IgE treatment efficacy. CD-max, the conventional approach to basophil allergen challenge, which mirrors cell reactivity, gives incorrect information.
Nopp
A
A
Clinical Immunology and Allergy Unit, Department of Medicine, Karolinska Institute, Stockholm, Sweden.
Johansson
S G O
SG
Ankerst
J
J
Bylin
G
G
Cardell
L O
LO
Grönneberg
R
R
Irander
K
K
Palmqvist
M
M
Oman
H
H
D000485:Allergens / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000008:administration & dosage*; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001249:Asthma / Q000188:drug therapy / Q000276:immunology; D001491:Basophils / Q000276:immunology*; D016022:Case-Control Studies; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005069:Evaluation Studies as Topic; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007114:Immunization; D007159:Immunologic Tests; D008297:Male; D009299:Nasal Provocation Tests; D000069444:Omalizumab; D011336:Probability; D012016:Reference Values; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D015854:Up-Regulation
D000485:Allergens; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C026408:anti-IgE antibodies; D000069444:Omalizumab