Department of Clinical Microbiology, Karlstad Hospital, Karlstad, Sweden; Centre for Clinical Research and Education, Region Värmland, Karlstad, Sweden.
Department of Science and Environment, PandemiX, Roskilde University, Roskilde, Denmark.
Clin Microbiol Infect. 2023 Dec;29(12):1561-1566. doi: 10.1016/j.cmi.2023.09.017. Epub 2023 Sep 26.
Lyme borreliosis (LB) is the most common tick-transmitted infection in the northern hemisphere and is caused by bacteria in the Borrelia burgdorferi sensu lato (Bbsl)-complex. The diagnosis is partially based on serology, and clinicians often take follow-up serum samples to look for seroconversion or an increase in IgG-antibody levels. In this registry-based study, we proposed a method for determining actual changes in IgG and examined antibody reactivity and decay.
Serological data from the departments of clinical microbiology at Karlstad Hospital, Sweden, and Slagelse Hospital, Denmark, were used to calculate a seroreactivity cut-off (SCOFF), above which changes between two samples from the patient cannot be explained by random variation. Increases in IgG reactivity as well as IgG and IgM decay were illustrated using time-to-event analysis and the SCOFF.
A total of 44,861 serum samples from 34,157 patients were tested for Bbsl-antibodies. Of the 4301 patients with follow-up samples taken within 100 days, 201 (4.67%) were above the SCOFF of 1.42 with a median time to follow-up sample of 36 days (interquartile range: 21). IgG demonstrated longer median time for all antibody levels (indeterminate: 4.6 years, low: 7.0 years, moderate-high: 8.8 years) than IgM antibodies (indeterminate: 2.1 years, low: 3.9 years, moderate-high: 6.8 years) and higher initial antibody levels persisted significantly longer for both IgG and IgM antibodies (p < 0.001). Of the 7868 patients with follow-up samples, isolated IgM reactivity preceded an increase in IgG reactivity in 18 patients (0.23%).
The SCOFF indicated little biological and random variation for Bbsl-specific IgG antibodies on the platforms used during the study. In most follow-up samples, both IgG and IgM antibodies persisted for years, with longer seropositivity associated with high initial antibody levels and IgG-type antibodies. The diagnostic value of isolated IgM reactivity was limited.
莱姆病（LB）是北半球最常见的蜱传感染，由伯氏疏螺旋体复合群（Bbsl）中的细菌引起。该诊断部分基于血清学，临床医生经常采集后续血清样本以寻找血清转换或 IgG 抗体水平升高。在这项基于登记的研究中，我们提出了一种确定 IgG 实际变化的方法，并检查了抗体反应性和衰减。
使用瑞典卡尔斯塔德医院和丹麦斯拉格斯勒医院临床微生物学系的血清学数据计算血清反应性截断值（SCOFF），超过该值，患者两次样本之间的变化不能用随机变异来解释。使用时间事件分析和 SCOFF 说明了 IgG 反应性以及 IgG 和 IgM 衰减的增加。
共检测了 34157 名患者的 44861 份血清样本，用于检测 Bbsl 抗体。在 4301 名接受 100 天内随访样本的患者中，201 名（4.67%）的 SCOFF 值超过 1.42，中位数随访样本时间为 36 天（四分位间距：21）。与 IgM 抗体相比，IgG 显示所有抗体水平的中位时间更长（不确定：4.6 年，低：7.0 年，中高：8.8 年）（不确定：2.1 年，低：3.9 年，中高：6.8 年），并且初始抗体水平较高的情况持续时间显著更长（p<0.001）。在 7868 名接受随访样本的患者中，18 名（0.23%）患者的孤立 IgM 反应性先于 IgG 反应性增加。
SCOFF 表明，在所使用的平台上，Bbsl 特异性 IgG 抗体的生物学和随机变异很小。在大多数随访样本中，IgG 和 IgM 抗体持续存在多年，较高的初始抗体水平和 IgG 型抗体与较长的血清阳性持续时间相关。孤立 IgM 反应性的诊断价值有限。
