Passive IgE‐sensitization by blood transfusion

Background: To study the mechanisms of passive sensitization of patients receiving plasma containing IgE antibodies to a defined allergen. Methods: When required for medical reasons, regular donor plasma with IgE antibodies to timothy grass allergen (8–205 kUA/l), was given. Kinetics of IgE antibodies in the recipients’ serum and his/her basophil allergen threshold sensitivity, CD‐sens, was monitored up to 2–3 weeks after transfusion. The IgE antibodies were quantitated by ImmunoCAP. The CD‐sens in plasma recipients, determined by CD63 up‐regulation, was measured by flow cytometry and compared to CD‐sens of patients with allergic asthma and/or rhinitis. Results: There was a significant correlation (r = 0.98; P