Abstract Details

Title Antibody screening using a tissue-based assay facilitates prompt induction of immunotherapy for autoimmune encephalitis

Topic Autoimmune Neurology

Presentation(s) P11 - Poster Session 11 (8:00 AM-9:00 AM)

Poster/Presentation
Number 15-009

Objective To evaluate whether antibody screening using an in-house tissue-based assay (TBA) facilitates the early identification of autoimmune encephalitis (AE) and leads to prompt induction of immunotherapy in patients with encephalitis.

Background

Recent evidence has revealed that patients with antibodies against neuronal surface proteins (NSAbs) respond well to intensive immunotherapies, and autoantibody screening with TBA allows immediate and systematic screening of NSAbs. However, it is unclear how TBA helps in the early diagnosis of AE and prompt induction of immunotherapy.

Design/Methods This prospective study was approved by our institutional review board. The study enrolled all adult patients with encephalitis admitted to our institution from July 1, 2017 to August 31, 2019. An in-house TBA, which was an immunohistochemical assay involving frozen rat brain sections, was used for antibody screening of cerebrospinal fluid. In samples with positive or questionable results, the specific antigens of the antibodies were confirmed by a cell-based assay or line blot.

Results The study included 68 patients with encephalitis. The median patient age was 48 (18–78) years, and 41 (64%) were female. The samples of 17 (25%) patients were positive in TBA (7 with typical neuropil [5 NMDAR, 1 LGI1, and 1 GABA_B], 1 atypical [GAD 65], 2 onconeural [1 ANNA1 and 1 Yo], 3 astrocytic [2 AQP4 and 1 GFAP], 1 white matter [MOG], and 3 positive in TBA alone [CBA negative]). The median interval for the screening result was 2 (2–5) days. All 17 patients, except those with onconeural antibodies, responded well to intensive immunotherapy and showed a favorable outcome (median mRS 2). Of the 17 patients, 3 received intravenous cyclophosphamide and 1 rituximab, with positive TBA results before antigen confirmation.

Conclusions The TBA promptly identified NSAbs, onconeural antibodies, and antibodies against astrocytes and MOG. This assay can facilitate early diagnosis and prompt induction of immunotherapy for AE.

Authors/Disclosures
Makoto Hara, MD (Nihon University School of Medicine) PRESENTER	Dr. Hara has nothing to disclose.
Hideto Nakajima, MD (Seikeikai Hospital)	No disclosure on file
	No disclosure on file
Tomotaka Mizoguchi	Tomotaka Mizoguchi has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file

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