Pouclet-Courtemanche Hélène, Nguyen Tri-Bao, Skrobala Emilie, Boutoleau-Bretonnière Claire, Pasquier Florence, Bouaziz-Amar Elodie, Bigot-Corbel Edith, Schraen Susanna, Dumurgier Julien, Paquet Claire, Lebouvier Thibaud
CHU Nantes, Inserm CIC04, Department of Neurology, Centre Mémoire de Ressources et Recherche, Nantes, France.
CH Delafontaine, Saint-Denis, France.
Alzheimers Dement (Amst). 2019 Feb 15;11:161-169. doi: 10.1016/j.dadm.2019.01.001. eCollection 2019 Dec.
Patients with positive tauopathy but negative Aβ (A-T+) in the cerebrospinal fluid (CSF) represent a diagnostic challenge. The Aβ ratio supersedes Aβ and reintegrates "false" A-T+ patients into the Alzheimer's disease spectrum. However, the biomarker and clinical characteristics of "true" and "false" A-T+ patients remain elusive.
Among the 509 T+N+ patients extracted from the databases of three memory clinics, we analyzed T+N+ patients with normal Aβ and compared "false" A-T+ with abnormal Aβ ratio and "true" A-T+ patients with normal Aβ ratio, before CSF analysis and at follow-up.
24.9% of T+N+ patients had normal Aβ levels. Among them, 42.7% were "true" A-T+. "True" A-T+ had lower CSF tau than "false" A-T+ patients. 48.0% of "true" A-T+ patients were diagnosed with frontotemporal lobar degeneration before CSF analysis and 64.0% at follow-up, as compared with 6% in the "false" A-T+ group ( < .0001).
Frontotemporal lobar degeneration is probably the main cause of "true" A-T+ profiles.
脑脊液（CSF）中tau病变呈阳性但淀粉样蛋白β（Aβ）呈阴性（A-T+）的患者面临诊断挑战。Aβ比值取代了Aβ，并将“假性”A-T+患者重新纳入阿尔茨海默病谱系。然而，“真性”和“假性”A-T+患者的生物标志物和临床特征仍不明确。
在从三家记忆诊所的数据库中提取的509例T+N+患者中，我们分析了Aβ正常的T+N+患者，并在脑脊液分析前和随访时比较了Aβ比值异常的“假性”A-T+患者和Aβ比值正常的“真性”A-T+患者。
24.9%的T+N+患者Aβ水平正常。其中，42.7%为“真性”A-T+。“真性”A-T+患者脑脊液中的tau水平低于“假性”A-T+患者。48.0%的“真性”A-T+患者在脑脊液分析前被诊断为额颞叶痴呆，随访时为64.0%，而“假性”A-T+组为6%（<0.0001）。
额颞叶痴呆可能是“真性”A-T+特征的主要原因。
