- Pathology（RCPA）实验研究：25 份 IVIg/SCIg 制品在神经元 LIA、组织 IIF、GAD65 ELISA 上均可造成假阳性或滴度抬高；输注后的阳性需谨慎解读。
- 关键数字：10 g/L 时 LIA 阳性率 64%（厂商稀释则 0%）；IIF 几乎普遍阳性但非特异；GAD65 ELISA 平均滴度显著升高，3 例临床在 IVIg 后新出现 GAD65 阳性。
- 对本站读者：神经元抗体报告在患者近期接受 Ig 治疗前/后要交叉核对用药史。本站仅摘要（期刊 closed，ScienceDirect 对本站常 CF）。
收录范围：PubMed 英文摘要及中文翻译（abstract-only）。Unpaywall 标注 closed；ScienceDirect 对本站出口常 Cloudflare 拦截，未采集全文、图表与病例细节。
摘要
免疫球蛋白（Ig）制剂用于治疗多种免疫介导性疾病，包括自身免疫性神经系统疾病。静脉用免疫球蛋白（IVIg）与皮下用免疫球蛋白（SCIg）剂型均有供应。虽然 Ig 制剂可干扰免疫测定结果的判读，但其对神经元抗体筛查方法的具体影响尚不清楚。本研究取 25 份 Ig 制品，按 10 g/L 处理以反映生理 IgG 水平，再按厂商推荐稀释方案分别用于神经元线性免疫测定（LIA）、神经元组织间接免疫荧光（IIF）以及谷氨酸脱羧酶（GAD）65 酶联免疫吸附测定（ELISA）。为提供临床背景，文中以三例病例说明 GAD65 ELISA 与 Ig 干扰。结果：IVIg 与 SCIg 在神经元 LIA、组织 IIF 与 GAD65 ELISA 上均呈现可变阳性。于 10 g/L 时，25 份中 16 份（64%）神经元 LIA 阳性，信号强度中位数为 19（1+），而按厂商推荐稀释时无一阳性。在六个单独批次中，观察到可重复的抗体谱（GAD65、CV2/CRMP5、Titin、Zic4）。按厂商推荐稀释时，全部 Ig 制品均出现神经元组织 IIF 阳性染色；于 10 g/L 时 25 份中 22 份（88%）阳性；然而这些模式为非特异性，且与 LIA 或 GAD65 ELISA 结果无相关性。平均而言，所有 Ig 制品的 GAD65 ELISA 滴度均升高：10 g/L 时为 200.5 IU/mL，未稀释制剂为 441.4 IU/mL。三例患者在输注 IVIg 后 GAD65 ELISA 转为阳性，而此前滴度不可检出。在实验条件下观察到与免疫球蛋白相关的测定干扰，变异可能归因于混合供者 Ig、制品基质及工作稀释度。在常规浓度下，这些发现的诊断适用性因检测方法而异。综合来看，若在给予 Ig 制剂之后进行检测，结果判读需谨慎。
- Pathology (RCPA) experimental study: 25 IVIg/SCIg products can cause false-positive or elevated titres on neuronal LIA, tissue IIF and GAD65 ELISA — interpret post-infusion positives cautiously.
- Key numbers: at 10 g/L, LIA positivity 64% (0% at manufacturer dilution); IIF nearly universal but non-specific; GAD65 ELISA mean titres markedly raised; three patients newly GAD65-positive after IVIg.
- For readers: when reporting neuronal antibodies, cross-check recent Ig therapy. Abstract-only (closed access; ScienceDirect often Cloudflare-blocked here).
Scope: PubMed abstract only. Unpaywall lists closed access; ScienceDirect is often Cloudflare-blocked from this exit, so full text, figures and case details were not collected.
Abstract
Immunoglobulin (Ig) products are prescribed for the treatment of a range of immune-mediated disorders, including autoimmune neurological disease. Both intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) formulations are available. While Ig products can interfere with immunoassay result interpretation, their influence on neuronal antibody screening methods specifically is unknown. Twenty-five Ig products were sourced and processed at 10 g/L to reflect physiological IgG levels, with these preparations then subjected to the manufacturer-recommended dilution protocols for neuronal line immunoassay (LIA), neuronal tissue indirect immunofluorescence (IIF) and glutamic acid decarboxylase (GAD) 65 enzyme-linked immunosorbent assay (ELISA). To provide clinical context, three cases are illustrated, specifically for GAD65 ELISA and Ig interference. Both IVIg and SCIg demonstrated variable positivity across neuronal LIA, tissue IIF and GAD65 ELISA. At 10 g/L, 16 of 25 (64%) products were positive by neuronal LIA, with a median signal intensity of 19 (1+), whereas no products were positive at the manufacturer-recommended dilution. In six individual batches, a reproducible antibody profile was observed (GAD65, CV2/CRMP5, Titin, Zic4). Positive neuronal tissue IIF staining was observed for all Ig products at the manufacturer-recommended dilution and for 22 of 25 (88%) of products at 10 g/L; however, the patterns were non-specific and showed no correlation with LIA or GAD65 ELISA results. On average, GAD65 ELISA titres were elevated for all Ig products: 200.5 IU/mL at 10 g/L and 441.4 IU/mL for neat preparations. Three patients developed positive GAD65 ELISA results after IVIg, having previously shown no detectable titres. Immunoglobulin-related assay interference was observed under experimental conditions, with variations likely attributable to pooled donor Ig, product matrices and the working dilution. Under routine concentrations, the diagnostic applicability of these findings varied by assay. Collectively, these findings highlight the need for cautious interpretation of results if performed after the administration of Ig products.