Department of Laboratory Medicine, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, P.R. China.
Faculty of Laboratory Medicine, Center for Translational Medicine, North Sichuan Medical college, Nanchong, Sichuan, P.R. China.
PLoS One. 2019 Mar 5;14(3):e0212893. doi: 10.1371/journal.pone.0212893. eCollection 2019.
The serological detection of antibodies to Treponema pallidum is essential to the diagnosis of syphilis. However, for the presence of cross-reaction, the specific antibody tests [e.g., enzyme-linked immunosorbent assay (ELISA)] always have false-positive results. In this study, we derived and validated the dissociation of urea in an attempt to alleviate the situation of false-positive antibodies to T. pallidum detected by ELISA. Six serum samples that were false-positive antibodies to T. pallidum detected by ELISA, and 16 control serum samples (8 sera positive for both specific IgG and IgM, and 8 IgG-positive and IgM-negative sera) were collected to select the appropriate dissociated concentration and time of urea. Our goal was to establish improved an ELISA method based on the original detection system of ELISA. The sensitivity of the improved ELISA was evaluated by 275 serum samples with class IgM-positive antibodies to T. pallidum. At 6 mol/L with 10 minutes dissociation of urea, 6 samples with false-positive antibodies to T. pallidum were converted to negative, and compared with true-positive antibodies to T. pallidum. The sensitivity of the improved ELISA was 100% by detecting the class IgM-positive antibodies to T. pallidum in sera of patients with syphilis. Considering the importance at the diagnosis of syphilis, antibodies to T. pallidum in serum samples should be retested by the improved ELISA method to avoid false-positive results.
梅毒螺旋体抗体的血清学检测对梅毒的诊断至关重要。然而，由于存在交叉反应，特定的抗体检测（如酶联免疫吸附试验（ELISA））总会出现假阳性结果。在本研究中，我们通过尿素解离来缓解 ELISA 检测到的梅毒螺旋体抗体假阳性的情况。从 6 份 ELISA 检测到的梅毒螺旋体抗体假阳性血清样本和 16 份对照血清样本（8 份特异性 IgG 和 IgM 均为阳性，8 份 IgG 阳性且 IgM 阴性）中选择合适的尿素解离浓度和时间。我们的目标是在原有的 ELISA 检测系统基础上建立改良的 ELISA 方法。通过对 275 份 IgM 阳性梅毒螺旋体抗体血清样本进行评估，确定改良 ELISA 的灵敏度。在 6mol/L 浓度下解离 10 分钟后，6 份假阳性梅毒螺旋体抗体样本转化为阴性，并与真阳性梅毒螺旋体抗体进行比较。改良 ELISA 检测梅毒螺旋体抗体 IgM 阳性血清样本的灵敏度为 100%。考虑到在梅毒诊断中的重要性，应对血清样本中的梅毒螺旋体抗体进行改良 ELISA 方法的重新检测，以避免假阳性结果。
