Purpose: To investigate inter- and intra-individual variation in the levels and outputs (concentration multiplied by salivary flow rate) of salivary metabolites in patients with primary Sjögren’s syndrome (pSS).

Methods: A total of 56 samples of stimulated saliva were collected from 14 female pSS patients during four laboratory visits within 20 weeks and analyzed using proton nuclear magnetic resonance spectroscopy. Single saliva samples from each of 15 controls were also analyzed.

Results: Among 21 quantified metabolites, choline was significantly elevated in the pSS patients at each time point (P ≤ 0.015), taurine at the last three time points (P ≤ 0.013), alanine at the last two time points (P ≤ 0.007) and glycine at the last time point (P = 0.005). Inter-individual variation in metabolite concentrations was generally larger among the patients than among the controls, and significantly large variations were observed for glycine (P ≤ 0.007, all time points), choline (P ≤ 0.033, three last time points) and alanine (P = 0.028, baseline). Metabolite output analysis showed that choline had the lowest intra-patient variation.

Conclusion: In spite of considerable intra- and inter-individual variation, levels and outputs of specific metabolites in patients with pSS differ from those in controls, and may be potentially applicable as new biological markers for monitoring of the response to treatment.

目的：研究原发性干燥综合征（pSS）患者唾液代谢物的水平和输出（浓度乘以唾液流速）的个体间和个体内变化。

方法：在20周内的4次实验室访问中，从14名女性pSS患者中收集了56份刺激唾液样本，并使用质子核磁共振波谱进行了分析。还分析了来自15个对照组中每个对照组的单个唾液样本。

结果：在21种量化的代谢物，胆碱在PSS患者被显著升高在每个时间点（P ≤0.015），牛磺酸在最后三个时间点（P ≤0.013），丙氨酸在最后两个时间点（P ≤0.007）和甘氨酸在最后一个时间点（P = 0.005）。在代谢物浓度的个体间变异之间的患者比对照中一般较大，并观察甘氨酸（显著大的变化P ≤0.007，所有时间点），胆碱（P ≤0.033，最后三个时间点）和丙氨酸（P= 0.028（基准）。代谢物输出分析表明，胆碱患者的变异最小。

结论：尽管个体间和个体间差异很大，但pSS患者中特定代谢物的水平和输出与对照组相比有所不同，并且可能潜在地用作监测治疗反应的新的生物学标记。