Brickshawana Adipong, Hinson Shannon R, Romero Michael F, Lucchinetti Claudia F, Guo Yong, Buttmann Mathias, McKeon Andrew, Pittock Sean J, Chang Min-Hwang, Chen An-Ping, Kryzer Thomas J, Fryer James P, Jenkins Sarah M, Cabre Philippe, Lennon Vanda A
Department of Immunology, Mayo Clinic, Rochester, MN, USA; Department of Neurology, Mayo Clinic, Rochester, MN, USA.
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
Lancet Neurol. 2014 Aug;13(8):795-806. doi: 10.1016/S1474-4422(14)70141-3. Epub 2014 Jul 6.
Antibodies have been implicated in the pathogenicity of multiple sclerosis by findings of immunoglobulins in patients' CSF and often IgG and complement in lesions, and by a 2012 report that nearly half of patients' serum samples contain IgG specific for a glial potassium-channel, KIR4.1. We aimed to establish the frequency of KIR4.1-binding IgG in serum and CSF of patients with multiple sclerosis, and whether KIR4.1 immunoreactivity is retained or lost in demyelinating lesions.
Using ELISA with a KIR4.1 peptide, we tested archival serum from 229 population-based and 57 clinic-based patients with multiple sclerosis, 99 healthy controls, and 109 disease controls, and CSF from 25 patients with multiple sclerosis and 22 disease controls. We tested all CSF and serum samples from 50 of the clinic-based patients with multiple sclerosis on cells expressing functional KIR4.1, using cell-based immunofluorescence and immunoprecipitation (solubilised recombinant human KIR4.1). We assessed KIR4.1 immunoreactivity in archival brain samples from 15 patients with histopathologically confirmed multiple sclerosis (22 plaques [eight early active, eight inactive, and six remyelinated], 13 periplaque regions and eight normal-appearing white-matter and grey-matter regions) and from three controls with non-neurological diseases.
Three of 286 serum samples from patients with multiple sclerosis and two of 208 serum samples from controls showed KIR4.1 reactivity on ELISA; none of the CSF samples from patients or controls showed KIR4.1 reactivity. IgG in none of the 50 serum samples from clinic-based patients immunoprecipitated KIR4.1, but a commercial KIR4.1-specific control IgG did. By immunofluorescence, one of 50 serum samples from patients with multiple sclerosis yielded faint plasmalemmal staining on both KIR4.1-expressing and non-expressing cells; 16 bound faintly to intracellular components. In all cases, IgG binding was quenched by absorption with liver powder or lysates from non-transfected cells. Binding by the KIR4.1-specific control IgG was quenched only by lysates containing KIR4.1. IgG in none of the 25 CSF samples from patients with multiple sclerosis bound to KIR4.1-transfected cells. Glial KIR4.1 immunoreactivity was increased relative to expression in healthy control brain in all active demyelinating lesions, remyelinated lesions, and periplaque white matter regions.
We did not detect KIR4.1-specific IgG in serum or CSF from patients with multiple sclerosis or KIR4.1 loss from glia in multiple sclerosis lesions. Serological testing for KIR4.1-specific IgG is unlikely to aid diagnosis of multiple sclerosis. The target antigen of multiple sclerosis remains elusive.
The National Institutes of Health, the National Multiple Sclerosis Society, and the Mayo Clinic Robert and Arlene Kogod Center on Aging.
通过在患者脑脊液中发现免疫球蛋白，以及在病变中常发现IgG和补体，并且2012年有报告称近一半患者的血清样本含有针对胶质钾通道KIR4.1的IgG，提示抗体与多发性硬化的致病性有关。我们旨在确定多发性硬化患者血清和脑脊液中KIR4.1结合IgG的频率，以及在脱髓鞘病变中KIR4.1免疫反应性是保留还是丧失。
使用KIR4.1肽进行酶联免疫吸附测定（ELISA），我们检测了229例基于人群和57例基于临床的多发性硬化患者的存档血清、99名健康对照和109名疾病对照，以及25例多发性硬化患者和22名疾病对照的脑脊液。我们使用基于细胞的免疫荧光和免疫沉淀法（可溶性重组人KIR4.1），对50例基于临床的多发性硬化患者的所有脑脊液和血清样本在表达功能性KIR4.1的细胞上进行检测。我们评估了15例经组织病理学确诊的多发性硬化患者（22个斑块[8个早期活动性、8个非活动性和6个再髓鞘化]、13个斑块周围区域以及8个外观正常的白质和灰质区域）和3例非神经系统疾病对照的存档脑样本中的KIR4.1免疫反应性。
286例多发性硬化患者的血清样本中有3例以及208例对照血清样本中有2例在ELISA中显示KIR4.1反应性；患者或对照的脑脊液样本均未显示KIR4.1反应性。50例基于临床的多发性硬化患者的血清样本中没有IgG免疫沉淀KIR4.1，但一种商业化的KIR4.1特异性对照IgG可以。通过免疫荧光法，50例多发性硬化患者的血清样本中有1例在表达KIR4.1和不表达KIR4.1的细胞上均产生微弱的质膜染色；16例与细胞内成分微弱结合。在所有情况下，IgG结合可被肝粉或未转染细胞裂解物吸收而淬灭。KIR4.1特异性对照IgG的结合仅被含有KIR4.1的裂解物淬灭。25例多发性硬化患者的脑脊液样本中没有IgG与KIR4.1转染细胞结合。相对于健康对照脑内的表达，在所有活动性脱髓鞘病变、再髓鞘化病变和斑块周围白质区域中，胶质KIR4.1免疫反应性均增加。
我们在多发性硬化患者的血清或脑脊液中未检测到KIR4.1特异性IgG，也未发现多发性硬化病变中胶质细胞的KIR4.1缺失。对KIR4.1特异性IgG的血清学检测不太可能有助于多发性硬化的诊断。多发性硬化的靶抗原仍然难以捉摸。
美国国立卫生研究院、美国国家多发性硬化症协会以及梅奥诊所罗伯特和阿琳·科戈德衰老研究中心。
