Abstract Details

Title Clinical and Immunological Investigations in Patients with Suspected Autoimmune Post-Herpes Simplex Encephalitis

Topic Autoimmune Neurology

Presentation(s) S39 - Autoimmune and Paraneoplastic Neurological Disorders: Clinical Characteristics and Diagnosis (1:24 PM-1:36 PM)

Poster/Presentation
Number 003

Objective To report the clinical and immunological features of patients with suspected autoimmune post-herpes simplex encephalitis (Post-HSE).

Background

Post-HSE is an autoimmune encephalitis triggered by HSE and occurs in 27% of patients with HSE. Post-HSE is associated with development of neuronal surface antibodies (NS-Abs); however, NS-Abs are not always identified in patients with suspected Post-HSE, and the cause of NS-Ab-negative cases remains unclear.

Design/Methods

This study included 6 patients with suspected Post-HSE (median age, 58.5 years [33-68]; 4 [66.7%] male) who underwent testing for NS-Abs between January 1, 2016 and April 30, 2019. Post-HSE was suspected because neuro-psychiatric symptoms worsened or newly developed but no reactivation of herpes simplex virus type 1 (HSV-1) was confirmed in CSF. The clinical features were compared between patients with and without NS-Abs.

Results HSV-1 DNA was detected in CSF at onset of HSE but not at relapse. Median interval from HSE onset to relapse was 31 days (range, 9-78 days). Main relapsing symptoms included abulia/depression/slow thinking (n=4), followed by fever (n=2) and involuntary movements/decreased consciousness level (n=1). Median CSF WBCs at relapse were 15.5/mm³ (6-485). OCBs were detected in 5/5. NS-Abs were identified in 3 (50%); 2 NMDAR and 1 against unknown antigens. Compared with NS-Ab-negative patients, NS-Ab-positive patients had longer median interval (50 days vs 11 days) with clear convalescent period after HSE and lower median CSF pleocytosis at relapse (7/mm³ vs 128/mm³). In 5 of 6 patients initial lesions expanded at relapse. All patients received immunotherapy; 6 high-dose steroids, 3 immunoglobulins, 1 cyclophosphamide. Outcome was poor (defined as mRS≥3) in 4 (66.7%) patients at the last followed-up (median 10 months, range 6.3-26.9); the outcome was good in 2 (mRS≤2).

Conclusions NS-Abs were identified in 50% of patients with suspected Post-HSE. The pathophysiology of early worsening without NS-Abs production may be different from that of NS-Ab-positive Post-HSE.

Authors/Disclosures
Juntaro Kaneko PRESENTER	Juntaro Kaneko has nothing to disclose.
Takahiro Iizuka, MD (Department of Neurology, Kitasato University School of Medicine)	The institution of Dr. Iizuka has received research support from EUROIMMUN Japan Co., Ltd.
	No disclosure on file
	No disclosure on file
Atsushi Kaneko	No disclosure on file
Eiji Kitamura	Eiji Kitamura has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Naomi Kanazawa	Naomi Kanazawa has nothing to disclose.
Kazutoshi Nishiyama, MD, PhD	Kazutoshi Nishiyama, MD, PhD has nothing to disclose.

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