Hjortlund Janni, Mortz Charlotte Gotthard, Stage Tore Bjerregaard, Skov Per Stahl, Dahl Ronald, Bindslev-Jensen Carsten
Department of Dermatology and Allergy Centre, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark.
Clinical Pharmacology, Institute of University of Southern Denmark, Odense C, Denmark.
Clin Transl Allergy. 2014 Oct 29;4:34. doi: 10.1186/2045-7022-4-34. eCollection 2014.
The positive and negative predictive values of specific IgE to penicillins are not well established for penicillin hypersensitivity. One reason may be that serum IgE levels to penicillin diminish over time. The objective in this study was to investigate variations in serum half-life (T½) for specific IgE to penicillins (s-IgE) and to evaluate the outcome of penicillin challenges in patients with previous but not present specific IgE to penicillins.
Two subgroups were investigated. All included patients had a history of penicillin allergy with reported symptoms such as urticaria/angioedema or unclassified cutaneous rash. T½ of specific IgE to penicillins was calculated based on sera from 29 patients with repeated measurements of s-IgE. Twenty-two patients with a previous positive s-IgE was followed and challenged with penicillin when IgE had become negative.
The T½ for s-IgE varied between the 26 patients with decreasing s-IgE from 1.6 months to 76.4 months and 52% had a T½ of less than a year. The three patients with stable and increasing IgE-values showed T½ approaching infinity A total of 29 challenges with β-lactams were performed. Four different patterns were seen when evaluating the clinical reaction to challenge (positive/negative) and post-challenge boost of s-IgE (yes/no). Eight (36.4%) had negative challenge and negative post-challenge s-IgE, eight (36.4%) negative challenge, but positive post-challenge s-IgE levels. 3 (13.6%) had positive challenge and positive post-challenge s-IgE whereas 3 (13.6%) were challenge positive, but had negative post-challenge s-IgE.
Specific IgE to penicillins declines over time stressing the importance of a close time relation between diagnostic work-up and clinical reaction. Reversal of previously positive s-IgE may still be associated with positive penicillin challenges and/or re-boostering of s-IgE to positivity.
针对青霉素过敏，特异性IgE对青霉素的阳性和阴性预测值尚未完全明确。一个原因可能是血清中针对青霉素的IgE水平会随时间下降。本研究的目的是调查青霉素特异性IgE（s-IgE）的血清半衰期（T½）变化，并评估既往有但目前已不存在青霉素特异性IgE的患者青霉素激发试验的结果。
对两个亚组进行了研究。所有纳入患者均有青霉素过敏史，伴有荨麻疹/血管性水肿或未分类皮疹等症状。基于29例重复测量s-IgE的患者血清计算青霉素特异性IgE的T½。对22例既往s-IgE呈阳性的患者进行随访，当IgE转阴后给予青霉素激发试验。
26例s-IgE水平下降的患者中，s-IgE的T½在1.6个月至76.4个月之间变化，52%的患者T½小于一年。3例IgE值稳定且升高的患者显示T½接近无穷大。共进行了29次β-内酰胺类药物激发试验。在评估激发试验的临床反应（阳性/阴性）和激发试验后s-IgE的升高情况（是/否）时发现了四种不同模式。8例（36.4%）激发试验阴性且激发试验后s-IgE阴性，8例（36.4%）激发试验阴性，但激发试验后s-IgE水平阳性。3例（13.6%）激发试验阳性且激发试验后s-IgE阳性，而3例（13.6%）激发试验阳性，但激发试验后s-IgE阴性。
青霉素特异性IgE会随时间下降，强调了诊断检查与临床反应之间密切时间关系的重要性。既往阳性的s-IgE转阴后仍可能与青霉素激发试验阳性和/或s-IgE再次升高至阳性有关。
