Author response: Hashimoto encephalopathy in the 21st century
FrancescGraus, Emeritus professor, Institut d'Investigació Biomèdica August Pi i Sunyer(IDIBAPS) (Barcelona, Spain)
Josep O.Dalmau, Director, Neuroimmunology laboratory, Institut d'Investigació Biomèdica August Pi i Sunyer(IDIBAPS) (Barcelona, Spain)
Submitted September 18, 2020
We thank Dr. Yoneda and colleagues for their comments on our article,1 arguing that the immunoblot using a purified recombinant ΝΗ2-terminal of α-enolase (NAE) protein is more sensitive than the immunoblot of HEK cell lysates expressing NAE.2 We agree that different methodological approaches could account for the discordant results. However, even assuming that the number of positive cases could be higher using purified NAE protein, the percentage of positive cases identified by Dr. Yoneda and colleagues—19/78 (24%)—is too low to consider NAE as a useful biomarker of Hashimoto encephalopathy. In addition to this low sensitivity, 4 (21%) of 19 patients with NAE antibodies had concurrent LGI1 antibodies, which were probably responsible for patients’ encephalitis.1 This brings the number of cases in which NAE antibodies were potential biomarkers of Hashimoto encephalopathy to 15 (19%). Overall, these data confirm that NAE antibodies have very limited clinical utility. Larger series of patients and appropriate controls will be crucial to confirm the clinical value of NAE antibodies in the diagnosis of Hashimoto encephalopathy. Current available evidence does not support the use of NAE antibodies for the diagnosis this disorder.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
Mattozzi S, Sabater L, Escudero D, et al. Hashimoto encephalopathy in the 21st century. Neurology 2020;94:e217–e224.
Kishitani T, Matsunaga A, Ikawa M, et al. Limbic encephalitis associated with anti-NH2-terminal of α-enolase antibodies: A clinical subtype of Hashimoto encephalopathy. Medicine (Baltimore) 2017;96:e6181.
We thank Dr. Yoneda and colleagues for their comments on our article,1 arguing that the immunoblot using a purified recombinant ΝΗ2-terminal of α-enolase (NAE) protein is more sensitive than the immunoblot of HEK cell lysates expressing NAE.2 We agree that different methodological approaches could account for the discordant results. However, even assuming that the number of positive cases could be higher using purified NAE protein, the percentage of positive cases identified by Dr. Yoneda and colleagues—19/78 (24%)—is too low to consider NAE as a useful biomarker of Hashimoto encephalopathy. In addition to this low sensitivity, 4 (21%) of 19 patients with NAE antibodies had concurrent LGI1 antibodies, which were probably responsible for patients’ encephalitis.1 This brings the number of cases in which NAE antibodies were potential biomarkers of Hashimoto encephalopathy to 15 (19%). Overall, these data confirm that NAE antibodies have very limited clinical utility. Larger series of patients and appropriate controls will be crucial to confirm the clinical value of NAE antibodies in the diagnosis of Hashimoto encephalopathy. Current available evidence does not support the use of NAE antibodies for the diagnosis this disorder.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References