Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
Department of Clinical Chemistry and Transfusion Medicine, Region Kalmar County, Kalmar, Sweden.
Clin Chem Lab Med. 2019 Nov 26;57(12):2008-2018. doi: 10.1515/cclm-2019-0315.
Background The aim of this study was to evaluate the diagnostic performance of cerebrospinal fluid (CSF) free light chains (FLCs) in the diagnosis of Lyme neuroborreliosis (LNB). Methods Serum and CSF levels of κ- and λ-FLC, albumin and total concentration of immunoglobulin M (IgM) were determined together with CSF chemokine CXCL13 in 23 patients with definite LNB, 35 inflammatory neurological disease control (INDC) and 18 non-inflammatory control (NIC) patients. Indices and intrathecal fractions (IFs) of FLC and IgM were calculated. Results Significant differences in FLC indices and IFs were found between the LNB group and both control groups, p ≤ 0.007. Sensitivity of intrathecal κ- and λ-FLC synthesis reached 78%-87% in LNB patients with a specificity of 94%-100% in NIC patients, whereas specificity in INDC patients was 69%. The corresponding frequencies of positive results for IF and index of IgM and CSF CXCL13 in these three diagnostic groups were 74%-96% in LNB patients, 0% in NIC patients and 3%-6% in INDC patients at the chosen cut-off levels. Conclusions The findings of this study show a moderate to high sensitivity of CSF κ- and λ-FLC in LNB patients with a high specificity in NIC patients. However, overlap in CSF κ- and λ-FLC levels between LNB and INDC patients calls for caution in the interpretation and limits the diagnostic usefulness in the LNB diagnosis. CSF CXCL13 appears to be the most valuable additional biomarker of LNB aside from routine parameters such as CSF pleocytosis and anti-Borrelia antibody index.
本研究旨在评估脑脊液（CSF）游离轻链（FLC）在诊断莱姆神经Borreliosis（LNB）中的诊断性能。
在 23 例明确的 LNB 患者、35 例炎症性神经疾病对照（INDC）和 18 例非炎症性对照（NIC）患者中，同时测定血清和 CSFκ-和λ-FLC、白蛋白和总免疫球蛋白 M（IgM）浓度以及 CSF 趋化因子 CXCL13。计算 FLC 指数和 IgM 的鞘内分数（IF）。
LNB 组与两组对照之间的 FLC 指数和 IF 差异有统计学意义，p≤0.007。LNB 患者鞘内κ-和λ-FLC 合成的敏感性为 78%-87%，NIC 患者的特异性为 94%-100%，而 INDC 患者的特异性为 69%。在这些三个诊断组中，IF 和 IgM 及 CSF CXCL13 指数的阳性结果频率在 LNB 患者中为 74%-96%，在 NIC 患者中为 0%，在 INDC 患者中为 3%-6%。
本研究结果显示，CSFκ-和λ-FLC 在 LNB 患者中有中度至高度敏感性，在 NIC 患者中有高度特异性。然而，LNB 和 INDC 患者的 CSFκ-和λ-FLC 水平重叠，这需要在解释时保持谨慎，限制了其在 LNB 诊断中的诊断实用性。CSF CXCL13 似乎是除 CSF 白细胞增多和抗 Borrelia 抗体指数等常规参数之外，诊断 LNB 的最有价值的附加生物标志物。
