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

Background: 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. Objectives: The aim of this study was to investigate whether tryptase can be detected in saliva of children following OFC. Method: 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. Results: 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 (p < 0.01). Conclusions: 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.背景：口服食物激发试验（Oral food challenge, OFC）是诊断食物过敏的常用手段，但该试验耗时且耗费资源，且由于依赖症状判读，结论并非总能明确。因此，寻找客观标志物可提升食物过敏诊断流程的准确性。 目标：本研究旨在探究儿童完成口服食物激发试验后，其唾液中能否检测到类胰蛋白酶（tryptase）。 方法：纳入标准为年龄3至18岁、被建议接受花生或坚果类口服食物激发试验的儿童。在激发试验首次给药前，以及末次给药后的5、10、15分钟采集唾液样本。在开展唾液类胰蛋白酶检测前，先对类胰蛋白酶免疫检测法的精密度、加标回收效果以及最低检测限进行验证。 结果：最终共纳入30名儿童，中位年龄为8岁，男性占比63.3%，口服食物激发试验结果阳性者占53.3%。唾液样本中可检测到类胰蛋白酶。与试验结果阴性的儿童相比，结果阳性者的基线类胰蛋白酶水平至各采样时间点的平均变化量存在显著差异（p < 0.01）。 结论：本研究证实，儿童完成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，受试者唾液类胰蛋白酶水平较基线显著升高，提示检测唾液类胰蛋白酶或可辅助食物过敏的诊断。未来仍需开展进一步研究，以评估类胰蛋白酶水平与症状之间的潜在关联。