Osbak Kara K, Tsoumanis Achilleas, De Baetselier Irith, Van Esbroek Marjan, Smet Hilde, Kenyon Chris R, Crucitti Tania
Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands.
BMJ Open. 2020 Sep 21;10(9):e035838. doi: 10.1136/bmjopen-2019-035838.
The diagnosis of repeat syphilis and its follow-up remains challenging. We aimed to investigate if IgM testing may assist in the diagnosis of syphilis reinfection/relapse and its treatment follow-up.
This substudy was conducted in the context of a syphilis biomarker discovery study (ClinicalTrials.gov Nr: NCT02059525). Sera were collected from 120 individuals with a new diagnosis of syphilis (72 with repeat infections) and 30 syphilis negative controls during a cohort study investigating syphilis biomarkers conducted at a sexually transmitted infection/HIV clinic in Antwerp, Belgium. Syphilis was diagnosed based on a simultaneous positive treponemal and non-treponemal assay result and/or positive serum PCR targeting . Specimens collected at visit of diagnosis, and 3 and 6 months post-treatment were tested by two enzyme immunoassays (EIAs), recomWell (Mikrogen; MI) and Euroimmun (EU), to detect anti-treponemal IgM. Baseline specimens were also tested for anti-treponemal IgM using a line immunoassay (LIA) recomLine (MI). Quantitative kinetic decay curves were constructed from the longitudinal quantitative EIA results.
An overall sensitivity for the diagnosis of syphilis of 59.8% (95% CI: 50.3%-68.7%), 75.0% (95% CI: 66.1%-82.3%) and 63.3% (95% CI: 54.8%-72.6%) was obtained for the EU, MI EIAs and MI LIA, respectively. When only considering repeat syphilis, the diagnostic sensitivity decreased to 45.7% (95% CI: 33.9%-58.0%), 63.9% (95% CI: 51.7%-74.6%) and 47.2% (95% CI: 35.5%-59.3%), respectively. IgM seroreverted in most cases 6 months after treatment. Post-treatment IgM concentrations decreased almost 30% faster for initial syphilis compared with repeat infection. The IgM EIAs and IgM LIA agreed from fairly to moderately (Cohen's kappa (κ): 0.36 (EU EIA); κ: 0.53 (MI EIA); κ: 0.40 (MI LIA)) with the diagnosis of syphilis.
IgM detection was not a sensitive method to diagnose syphilis and was even poorer in the diagnosis of syphilis repeat infections.
重复梅毒的诊断及其随访仍然具有挑战性。我们旨在研究IgM检测是否有助于梅毒再感染/复发的诊断及其治疗随访。
本亚研究是在一项梅毒生物标志物发现研究（ClinicalTrials.gov编号：NCT02059525）的背景下进行的。在比利时安特卫普的一家性传播感染/艾滋病诊所进行的一项调查梅毒生物标志物的队列研究中，收集了120例新诊断为梅毒的个体（72例有重复感染）和30例梅毒阴性对照的血清。梅毒的诊断基于梅毒螺旋体和非梅毒螺旋体检测结果同时呈阳性和/或针对……的血清PCR呈阳性。在诊断时以及治疗后3个月和6个月采集的标本通过两种酶免疫测定法（EIA），即recomWell（Mikrogen；MI）和Euroimmun（EU）进行检测，以检测抗梅毒螺旋体IgM。基线标本也使用线性免疫测定法（LIA）recomLine（MI）检测抗梅毒螺旋体IgM。根据纵向定量EIA结果构建定量动力学衰减曲线。
EU、MI EIA和MI LIA对梅毒诊断的总体敏感性分别为59.8%（95%CI：50.3%-68.7%）、75.0%（95%CI：66.1%-82.3%）和63.3%（95%CI：54.8%-72.6%）。仅考虑重复梅毒时，诊断敏感性分别降至45.7%（95%CI：33.9%-58.0%）、63.9%（95%CI：51.7%-74.6%）和47.2%（95%CI：35.5%-59.3%）。大多数情况下，IgM在治疗后6个月血清学转阴。与重复感染相比，初发性梅毒治疗后IgM浓度下降速度快近30%。IgM EIA和IgM LIA与梅毒诊断的一致性从中度到中等（Cohen's kappa（κ）：0.36（EU EIA）；κ：0.53（MI EIA）；κ：0.40（MI LIA））。
IgM检测不是诊断梅毒的敏感方法，在诊断梅毒重复感染方面甚至更差。
