Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Clin Infect Dis. 2021 Oct 5;73(7):e2355-e2361. doi: 10.1093/cid/ciaa858.
Laboratory confirmation of early Lyme borreliosis (LB) is challenging. Serology is insensitive during the first days to weeks of infection, and blood polymerase chain reaction (PCR) offers similarly poor performance. Here, we demonstrate that detection of Borrelia burgdorferi (B.b.) cell-free DNA (cfDNA) in plasma can improve diagnosis of early LB.
B.b. detection in plasma samples using unbiased metagenomic cfDNA sequencing performed by a commercial laboratory (Karius Inc) was compared with serology and blood PCR in 40 patients with physician-diagnosed erythema migrans (EM), 28 of whom were confirmed to have LB by skin biopsy culture (n = 18), seroconversion (n = 2), or both (n = 8). B.b. sequence analysis was performed using investigational detection thresholds, different from Karius' clinical test.
B.b. cfDNA was detected in 18 of 28 patients (64%) with laboratory-confirmed EM. In comparison, sensitivity of acute-phase serology using modified 2-tiered testing (MTTT) was 50% (P = .45); sensitivity of blood PCR was 7% (P = .0002). Combining B.b. cfDNA detection and MTTT increased diagnostic sensitivity to 86%, significantly higher than either approach alone (P ≤ .04). B.b. cfDNA sequences matched precisely with strain-specific sequence generated from the same individual's cultured B.b. isolate. B.b. cfDNA was not observed at any level in plasma from 684 asymptomatic ambulatory individuals. Among 3000 hospitalized patients tested as part of clinical care, B.b. cfDNA was detected in only 2 individuals, both of whom had clinical presentations consistent with LB.
This is the first report of B.b. cfDNA detection in early LB and a demonstration of potential diagnostic utility. The combination of B.b. cfDNA detection and acute-phase MTTT improves clinical sensitivity for diagnosis of early LB.
早期莱姆病（LB）的实验室确诊具有挑战性。在感染的最初几天到几周内，血清学检测不敏感，血液聚合酶链反应（PCR）的表现也同样不佳。在这里，我们证明了在血浆中检测游离 Borrelia burgdorferi（B.b.）DNA（cfDNA）可以提高早期 LB 的诊断。
使用商业实验室（Karius Inc）进行的无偏 metagenomic cfDNA 测序来检测血浆中的 B.b.，并将其与 40 名经医生诊断为游走性红斑（EM）的患者的血清学和血液 PCR 进行比较，其中 28 例通过皮肤活检培养（n=18）、血清学转换（n=2）或两者（n=8）证实为 LB。使用不同于 Karius 临床检测的研究性检测阈值进行 B.b.序列分析。
在 28 例经实验室确诊的 EM 患者中，有 18 例（64%）检测到 B.b. cfDNA。相比之下，使用改良的 2 级检测（MTTT）的急性相血清学的敏感性为 50%（P=0.45）；血液 PCR 的敏感性为 7%（P=0.0002）。将 B.b. cfDNA 检测与 MTTT 相结合，可将诊断敏感性提高到 86%，显著高于单独使用任何一种方法（P≤0.04）。B.b. cfDNA 序列与从同一个体培养的 B.b.分离株生成的菌株特异性序列完全匹配。在 684 名无症状门诊个体的血浆中，均未观察到任何水平的 B.b. cfDNA。在作为临床护理一部分进行测试的 3000 名住院患者中，仅在 2 名患者中检测到 B.b. cfDNA，他们的临床表现均与 LB 一致。
这是首次报道在早期 LB 中检测到 B.b. cfDNA，并证明了其潜在的诊断效用。B.b. cfDNA 检测与急性相 MTTT 的结合提高了早期 LB 的临床诊断敏感性。
