BACKGROUND Increasing evidence indicates that periodontitis contributes to systemic low-grade inflammation. Porphyromonas gingivalis is strongly associated with periodontitis, and antibodies against the bacterium may be used as a serological proxy to account for periodontal status, when studying diseases associated with periodontitis. The aim of the present study is to identify an easily accessible and reliable serological biomarker for determination of periodontal status and oral carriage of the bacterium. METHODS Saliva and serum samples were collected from periodontally healthy controls (n = 27), and patients with periodontitis stage II (n = 12) or stages III or IV (n = 44). Serum levels of immunoglobulin G (IgG) antibodies against intact and fragmented P. gingivalis, recombinant gingipains (RgpA and RgpB), and the bacteria Escherichia coli and Capnocytophaga ochracea as controls were quantified with a multiplex bead-based assay. P. gingivalis was identified in saliva using quantitative polymerase chain reaction (qPCR). RESULTS Serum IgG antibodies against P. gingivalis whole bacteria were good indicators of periodontitis (area under the curve [AUC]: 0.75, 95% confidence interval [CI]: 0.64-0.85). The same was observed for levels of antibodies against P. gingivalis fragments (AUC: 0.78, 95% CI: 0.68-0.88). Likewise, levels of antibodies against P. gingivalis whole bacteria or P. gingivalis fragments were good indicators of oral carriage of P. gingivalis (AUC: 0.92, 95% CI: 0.86-0.98 and AUC: 0.96, 95% CI: 0.92-1, respectively). Conversely, antibodies against recombinant RgpA and RgpB were not good indicators of periodontitis or oral carriage of the bacterium. None of the antibody levels differed significantly between stage II and stage III or IV periodontitis. CONCLUSION Serum IgG antibody levels against heat-inactivated whole P. gingivalis proved to be the preferable biomarker for periodontitis and oral carriage of the bacterium.

中文翻译：

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评估针对牙龈卟啉单胞菌或其牙龈蛋白酶的循环 IgG 抗体作为牙周炎和细菌携带的血清学标志物。


背景越来越多的证据表明牙周炎会导致全身低度炎症。牙龈卟啉单胞菌与牙周炎密切相关，在研究与牙周炎相关的疾病时，针对该细菌的抗体可用作解释牙周状态的血清学指标。本研究的目的是确定一种易于获取且可靠的血清学生物标志物，用于确定牙周状态和口腔携带细菌。方法 从牙周健康对照者 (n = 27) 以及 II 期牙周炎患者 (n = 12) 或 III 期或 IV 期牙周炎患者 (n = 44) 采集唾液和血清样本。使用基于多重微珠的测定法对针对完整和片段牙龈卟啉单胞菌、重组牙龈蛋白酶（RgpA 和 RgpB）以及作为对照的细菌大肠杆菌和赭二氧化碳噬菌体的免疫球蛋白 G (IgG) 抗体的血清水平进行定量。使用定量聚合酶链反应 (qPCR) 鉴定唾液中的牙龈卟啉单胞菌。结果 针对牙龈卟啉单胞菌全菌的血清 IgG 抗体是牙周炎的良好指标（曲线下面积 [AUC]：0.75，95% 置信区间 [CI]：0.64-0.85）。针对牙龈卟啉单胞菌片段的抗体水平也观察到了相同的情况（AUC：0.78，95% CI：0.68-0.88）。同样，针对牙龈卟啉单胞菌完整细菌或牙龈卟啉单胞菌片段的抗体水平是牙龈卟啉单胞菌口腔携带的良好指标（AUC：0.92，95％CI：0.86-0.98和AUC：0.96，95％CI：0.92-1 ， 分别）。相反，针对重组 RgpA 和 RgpB 的抗体并不是牙周炎或口腔携带细菌的良好指标。 II 期和 III 期或 IV 期牙周炎之间的抗体水平没有显着差异。 结论 热灭活的完整牙龈卟啉单胞菌的血清 IgG 抗体水平被证明是牙周炎和口腔携带细菌的优选生物标志物。