From the Translational Neuroscience Center (X.Z., J.K., T.I., M.M., G.M., Y. Nakamura), Graduate School of Medicine, International University of Health and Welfare, Okawa; School of Pharmacy at Fukuoka (J.K., T.I., Y. Nakamura), International University of Health and Welfare, Okawa; Department of Neurology (J.K., Y. Nakamura), Brain and Nerve Center, Fukuoka Central Hospital, International University of Health and Welfare, Fukuoka; Department of Neurology (H.O., T.F., R.Y., N.I.), Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka; Department of Neurology (M.K., K.K.), Tokyo Women's Medical University Hospital, Tokyo; Department of Cardiovascular Medicine (Y. Namihira, Y.O.), Nephrology, and Neurology, Graduate School of Medicine, University of Ryukyus, Okinawa; and Division of Membrane Physiology (Y.F., M.F.), National Institute for Physiological Sciences, Okazaki, Japan.
Neurol Neuroimmunol Neuroinflamm. 2023 Jan 11;10(2). doi: 10.1212/NXI.0000000000200081. Print 2023 Mar.
The objective of this study was to discover novel nodal autoantibodies in chronic inflammatory demyelinating polyneuropathy (CIDP).
We screened for autoantibodies that bind to mouse sciatic nerves and dorsal root ganglia (DRG) using indirect immunofluorescence (IFA) assays with sera from 113 patients with CIDP seronegative for anti-neurofascin 155 and anticontactin-1 antibodies and 127 controls. Western blotting, IFA assays using HEK293T cells transfected with relevant antigen expression plasmids, and cell-based RNA interference assays were used to identify target antigens. and expression, both of which independently control peripheral nerve myelination, was assessed by quantitative real-time PCR after application of patient and control sera to Schwann cells.
Sera from 4 patients with CIDP, but not control sera, selectively bound to the nodal regions of sciatic nerves and DRG satellite glia ( = 0.048). The main immunoglobulin G (IgG) subtype was IgG4. IgG from these 4 patients stained a 60-kDa band on Western blots of mouse DRG and sciatic nerve lysates. These features indicated leucine-rich repeat LGI family member 4 (LGI4) as a candidate antigen. A commercial anti-LGI4 antibody and IgG from all 4 seropositive patients with CIDP showed the same immunostaining patterns of DRG and cultured rat Schwann cells and bound to the 60-kDa protein in Western blots of LGI4 overexpression lysates. IgG from 3 seropositive patients, but none from controls, bound to cells cotransfected with plasmids containing LGI4 and a disintegrin and metalloprotease domain-containing protein 22 (ADAM22), an LGI4 receptor. In cultured rat Schwann and human melanoma cells constitutively expressing LGI4, siRNA effectively downregulated and reduced patients' IgG binding compared with scrambled siRNA. Application of serum from a positive patient to Schwann cells expressing ADAM22 significantly reduced the expression of , but not . Anti-LGI4 antibody-positive patients had a relatively old age at onset (mean age 58 years), motor weakness, deep and superficial sensory impairment with Romberg sign, and extremely high levels of CSF protein. Three patients showed subacute CIDP onset resembling Guillain-Barré syndrome.
IgG4 anti-LGI4 antibodies are found in some elderly patients with CIDP who present subacute sensory impairment and motor weakness and are worth measuring, particularly in patients with symptoms resembling Guillain-Barré syndrome.
本研究旨在发现慢性炎症性脱髓鞘性多发性神经病（CIDP）中的新型神经节自身抗体。
我们使用间接免疫荧光（IFA）检测血清中抗神经束蛋白 155 和抗接触蛋白-1 抗体阴性的 113 例 CIDP 患者和 127 例对照者的血清，以检测与小鼠坐骨神经和背根神经节（DRG）结合的自身抗体。使用 Western blot、用相关抗原表达质粒转染的 HEK293T 细胞中的 IFA 检测和基于细胞的 RNA 干扰检测来鉴定靶抗原。用定量实时 PCR 评估患者和对照者血清对施旺细胞的作用后，评估神经节段粘连蛋白 4（LGI4）和神经束蛋白 186 的表达，这两种蛋白均独立控制周围神经髓鞘形成。
4 例 CIDP 患者的血清而非对照者血清选择性地结合于坐骨神经和 DRG 卫星胶质的神经节区（=0.048）。主要免疫球蛋白 G（IgG）亚型为 IgG4。这 4 例患者的 IgG 在 Western blot 检测的小鼠 DRG 和坐骨神经裂解物中标记出 60 kDa 条带。这些特征表明富含亮氨酸重复 LGI 家族成员 4（LGI4）是候选抗原。商业抗 LGI4 抗体和来自 4 例血清阳性 CIDP 患者的 IgG 均显示相同的 DRG 和培养的大鼠施旺细胞免疫染色模式，并与 LGI4 过表达裂解物中的 60 kDa 蛋白结合。3 例血清阳性患者的 IgG 而非对照者 IgG 与含有 LGI4 和解整合素金属蛋白酶域蛋白 22（ADAM22）的质粒共转染的细胞结合。在持续表达 LGI4 的大鼠施旺细胞和人黑色素瘤细胞中，siRNA 有效地下调了 和减少了患者 IgG 的结合，与对照 siRNA 相比。阳性患者的血清应用于表达 ADAM22 的施旺细胞，显著降低了 ，但不降低 。抗 LGI4 抗体阳性患者的发病年龄较大（平均年龄 58 岁），存在运动无力、深感觉和浅感觉障碍伴 Romberg 征，脑脊液蛋白水平极高。3 例患者表现为类似于格林-巴利综合征的亚急性 CIDP 发作。
在一些老年 CIDP 患者中发现 IgG4 抗 LGI4 抗体，这些患者表现为亚急性感觉障碍和运动无力，值得测量，尤其是在症状类似于格林-巴利综合征的患者中。
