BACKGROUND: Skin test sensitivity in @entity1 with immediate @entity566 to penicillins tends to decrease over time, but no information is available concerning in vitro tests. We analysed the negativization rates of two in vitro methods that determine specific @entity9416 ( @entity9416 ) antibodies, the basophil activation test using flow cytometry (BAT) and the radioallergosorbent test (RAST), in immediate @entity56 to penicillins. METHODS: Forty-one @entity1 with immediate @entity56 to @entity115 were followed up over a 4-year period. BAT and RAST were performed at 6-month intervals. @entity1 were randomized into groups: Group I, skin tests carried out at regular intervals; Group II, skin tests made only at the beginning of the study. RESULTS: Differences were observed between RAST and BAT (P < 0.01), the latter showing earlier negativization. Considering different haptens, significant differences for the rate of negativization were only found for @entity115 (P < 0.05). Comparisons between Groups I (n = 10) and II (n = 31) showed a tendency to become negative later in Group I with RAST. CONCLUSIONS: Levels of specific @entity9416 antibodies tended to decrease over time in @entity1 with immediate @entity56 to @entity115 . Conversion to negative took longer for the RAST assay, although the differences were only detected with the @entity115 hapten. Skin testing influenced the rate of negativization of the RAST assay, contributing to maintenance of in vitro sensitivity. Because of the loss of sensitivity over time, the determination of specific @entity9416 antibodies to penicillins in @entity1 with immediate @entity56 must be done as soon as possible after the reaction.

Negativization rates of XXXX radioimmunoassay and basophil activation test in immediate reactions to penicillins.

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity115 :: ('MESH:D000658', 'Chemical') :: ['amoxicillin'] @entity566 :: ('MESH:D006967', 'Disease') :: ['allergy'] @entity56 :: ('MESH:D004342', 'Disease') :: ['allergic reactions'] @entity9416 :: ('3497', 'Gene') :: ['immunoglobulin E', 'IgE']
@entity9416 :: (3497,Gene) :: ['IgE']
