Supplementary Material for: Detection of Salivary Tryptase Levels in Children following Oral Food Challenges

<b><i>Background:</i></b> Oral food challenge (OFC) is commonly used to diagnose food allergy. This test is time and resource intensive, and conclusions are not always unequivocal as this relies on the interpretation of symptoms. Therefore, an objective marker would improve the accuracy of the diagnostic workup of food allergy. <b><i>Objectives:</i></b> The aim of this study was to investigate whether tryptase can be detected in saliva of children following OFC. <b><i>Method:</i></b> Children from 3 to 18 years of age were eligible for inclusion if an OFC for peanut or tree nut had been recommended. Saliva samples were collected prior to the first dose and 5, 10, and 15 min following the last administered dose during OFC. Assay precision, spike-and-recovery, and assessment of lower limit of detection of the tryptase immunoassay were examined before analysis of tryptase in saliva was performed. <b><i>Results:</i></b> A total of 30 children were included (median age 8 years, 63.3% male, 53.3% positive OFC outcome). Tryptase was detected in saliva samples. The mean of the change in baseline tryptase value to each saliva collecting time point was significantly different in patients with a positive OFC outcome compared to a negative outcome (<i>p</i> &lt; 0.01). <b><i>Conclusions:</i></b> This study showed that tryptase can be detected in saliva of children following OFC. Increased levels of tryptase compared to baseline were found if the OFC outcome was positive, suggesting that measuring tryptase in saliva may be useful in the diagnosis of food allergy. Further research is needed to evaluate the potential association between tryptase levels and symptoms.

<b><i>背景：</i></b> 口服食物激发试验（oral food challenge, OFC）是诊断食物过敏的常用手段。该检测方式耗时耗力，且结果并非总能明确判定——其结论依赖于症状的主观解读，因此寻找客观标志物可有效提升食物过敏诊断流程的准确性。<b><i>研究目的：</i></b> 本研究旨在探究儿童在接受口服食物激发试验后，其唾液中是否可检测到类胰蛋白酶（tryptase）。<b><i>研究方法：</i></b> 凡被推荐接受花生或坚果类口服食物激发试验的3~18岁儿童均可纳入本研究。在激发试验首次给药前，以及末次给药后的第5、10、15分钟采集唾液样本。在正式开展唾液类胰蛋白酶检测前，我们先对类胰蛋白酶免疫测定法的精密度、加标回收性能以及最低检测限进行了验证。<b><i>研究结果：</i></b> 本研究共纳入30名儿童，年龄中位数为8岁，男性占比63.3%，口服食物激发试验结果阳性者占53.3%。所有唾液样本中均检测到类胰蛋白酶。与试验结果阴性的患儿相比，阳性结果组患儿的唾液类胰蛋白酶水平相较于基线值的平均变化量存在显著统计学差异（*p* < 0.01）。<b><i>研究结论：</i></b> 本研究证实，儿童在接受口服食物激发试验后，其唾液中可检测到类胰蛋白酶。当口服食物激发试验结果为阳性时，患儿唾液类胰蛋白酶水平较基线值升高，提示检测唾液类胰蛋白酶或可辅助食物过敏的临床诊断。未来仍需开展进一步研究以评估类胰蛋白酶水平与症状间的潜在关联。