为了描述“仅可能”或“很可能”患有自身免疫性脑炎 (AE) 的患者的长期结果。尽管占 AE 病例的三分之一，但缺乏典型 AE 定义特征的抗体阴性病例尚未得到充分研究。我们进行了回顾性研究对 2006 年至 2020 年在三级神经免疫学实践中评估的成年患者进行分析，符合“仅可能”或“可能但抗体阴性”AE 的诊断标准，并进行至少一年的随访。所有患者均接受了神经抗体检测。纳入了 45 名患者（中位年龄 61 岁 [范围，20-88]；女性，21 名 [47%]），中位随访时间为 36 个月（范围，12-88 岁）。 174）。另外六名患者的诊断发生了变化，这些患者被排除在进一步分析之外，只有两名患者在随访期间接受了非自身免疫性诊断。大多数（41/45 [91%]）在基线时表现出明显的残疾（改良Rankin量表[mRS]≥3）。 20/44 (45%) 的脑脊液呈炎症，21/45 (47%) 的 MRI 异常。在组织检测中检测到未分类的神经特异性 IgG 染色，其中 5 例 (11%) 被检测到。两例 (4%) 具有副肿瘤原因。从发病到开始免疫治疗的中位时间为两个月（范围为 0-21），所有 44 例（98%）治疗病例至少得到部分改善。 14/45 (31%) 发生临床复发。在最后一次随访中，最常见的症状是记忆功能障碍（31/45 [69%]）、注意力缺陷（17/45 [38%]）、步态不稳定（13/45 [29%]）和视觉空间功能障碍（10/45 [22%]）。大多数患者实现了独立（中位 mRS，2 [范围，0-6]）；然而，11 名患者的神经学结果较差（mRS ≥ 3）。三个月时较高的 mRS 评分和步态辅助要求预示着不良结果 (P ≤ 0.01)。尽管在初始阶段存在明显残疾，但抗体阴性但临床推测 AE 的患者显示出通过免疫治疗得到改善的潜力，凸显了早期干预的重要性。早期功能状态和步态辅助需求可能有助于预测长期预后。

To characterize the long-term outcomes of patients with "possible only" or "probable" autoimmune encephalitis (AE).Despite comprising one-third of AE cases, antibody-negative cases lacking typical AE-defining features are understudied.We conducted a retrospective analysis of adult patients evaluated at a tertiary center neuroimmunology practice from 2006 to 2020, meeting diagnostic criteria for "possible only" or "probable but antibody-negative" AE, with at least one year of follow-up. All patients underwent neural antibody testing.Forty-five patients (median age, 61 years [range, 20-88]; female, 21 [47%]) were included, with a median follow-up of 36 months (range, 12-174). A change in diagnosis was noted in six additional patients, who were excluded from further analysis, with only two receiving a non-autoimmune diagnosis during follow-up. The majority (41/45 [91%]) presented with significant disability (modified Rankin Scale [mRS] ≥3) at baseline. CSF was inflammatory in 20/44 (45%) and MRI was abnormal in 21/45 (47%). Unclassified neural-specific IgG staining on tissue-based assay was detected in five (11%). Two cases (4%) had a paraneoplastic cause. The median time from onset to immunotherapy initiation was two months (range, 0-21), resulting in at least partial improvement in all 44 (98%) treated cases. Clinical relapses occurred in 14/45 (31%). At last follow-up, the most common symptoms were memory dysfunction (31/45 [69%]), attention deficits (17/45 [38%]), gait instability (13/45 [29%]), and visuospatial dysfunction (10/45 [22%]). Most patients achieved independence (median mRS, 2 [range, 0-6]); however, 11 patients had poor neurological outcome (mRS ≥3). Higher mRS score and gait assistance requirement at three months were predictive of poor outcome (P ≤0.01).Despite significant disability at initial stages, patients with antibody-negative but clinically presumed AE show potential for improvement with immunotherapy, highlighting the importance of early intervention. Early functional status and gait assistance requirements may assist in predicting long-term prognosis.