Serological profiling of the EBV immune response in Chronic Fatigue Syndrome using a peptide microarray

Background Epstein-Barr-Virus (EBV) plays an important role as trigger or cofactor for various autoimmune diseases. In a subset of patients with Chronic Fatigue Syndrome (CFS) disease starts with infectious mononucleosis as late primary EBV-infection, whereby altered levels of EBV-specific antibodies can be observed in another subset of patients. Methods We performed a comprehensive mapping of the IgG response against EBV comparing 50 healthy controls with 92 CFS patients using a microarray platform. Patients with multiple sclerosis (MS), systemic lupus erythematosus (SLE) and cancer-related fatigue served as controls. 3054 overlapping peptides were synthesised as 15-mers from 14 different EBV proteins. Array data was validated by ELISA for selected peptides. Prevalence of EBV serotypes was determined by qPCR from throat washing samples. Results EBV type 1 infections were found in patients and controls. EBV seroarray profiles between healthy controls and CFS were less divergent than that observed for MS or SLE. We found significantly enhanced IgG responses to several EBNA-6 peptides containing a repeat sequence in CFS patients compared to controls. EBNA-6 peptide IgG responses correlated well with EBNA-6 protein responses. The EBNA-6 repeat region showed sequence homologies to various human proteins. Conclusion Patients with CFS had a quite similar EBV IgG antibody response pattern as healthy controls. Enhanced IgG reactivity against an EBNA-6 repeat sequence and against EBNA-6 protein is found in CFS patients. Homologous sequences of various human proteins with this EBNA-6 repeat sequence might be potential targets for antigenic mimicry.### 背景 EB病毒（Epstein-Barr Virus, EBV）作为多种自身免疫性疾病的触发因素或辅助因子发挥关键作用。在慢性疲劳综合征（Chronic Fatigue Syndrome, CFS）患者中，部分亚组的发病以传染性单核细胞增多症为表现，该病症对应原发性EBV感染的晚期阶段；另有部分亚组患者可检测到EBV特异性抗体水平异常。 ### 方法 本研究采用微阵列平台，纳入50名健康对照者与92名CFS患者，对针对EBV的IgG抗体应答进行全面图谱绘制。本研究设置多发性硬化（Multiple Sclerosis, MS）、系统性红斑狼疮（Systemic Lupus Erythematosus, SLE）及癌因性疲劳患者作为对照。从14种不同的EBV蛋白中合成了3054条15肽重叠肽段。通过酶联免疫吸附试验（Enzyme-Linked Immunosorbent Assay, ELISA）对筛选出的肽段进行阵列数据验证。通过对咽拭子洗液样本开展实时定量聚合酶链反应（Quantitative Polymerase Chain Reaction, qPCR），确定EBV血清型的流行率。 ### 结果 患者与对照人群中均检测到EBV 1型感染。健康对照者与CFS患者的EBV血清抗体阵列图谱差异，小于MS或SLE患者与对应对照人群的差异。相较于对照组，CFS患者针对数种含重复序列的EB病毒核抗原6（Epstein-Barr Nuclear Antigen 6, EBNA-6）肽段的IgG应答显著增强。EBNA-6肽段的IgG应答与EBNA-6蛋白的应答呈现良好相关性。EBNA-6重复区域与多种人类蛋白存在序列同源性。 ### 结论 CFS患者的EBV IgG抗体应答模式与健康对照者较为相似。CFS患者针对EBNA-6重复序列及EBNA-6蛋白的IgG反应性显著增强。该EBNA-6重复序列与多种人类蛋白的同源序列，可能成为抗原模拟的潜在靶点。