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Advanced Neurology The diagnosis and treatment of anti-LGI1 autoimmune encephalitis

studies are required to further determine the causes of Acknowledgments
recurrence.
None.
A mortality rate of 6% has been reported in patients with
anti-LGl1 AE . Persistent cognitive impairment is a long- Funding
[78]
term sequela of patients with anti-LGl1 AE, especially in None.
the absence of early and appropriate immunotherapy. This
irreversible cognitive impairment in patients may be due Conflict of interest
to high levels of LGI1 antibody in their cerebrospinal fluid,
followed by complement deposition and hippocampal The authors report no conflict of interest.
atrophy [49,78-80] . Thompson et al. [31,78] have emphasized Author contributions
the importance of early and effective immunotherapy
for patients. For each week of delay in immunotherapy, Conceptualization: Ying-Feng Mu, De-Qin Geng
the possibility of FBDS resolution decreases by 5%. If Supervision: De-Qin Geng
FBDS persists for more than 90 days, more than half of Writing – original draft: Ning Gu, Tian-Yue Meng, Zhuang
the patients will develop cognitive impairment. The time Zhu, Bao-Xin Wu
needed to recover from cognitive impairment is associated Writing – review & editing: Ying-Feng Mu, De-Qin Geng
with the time immunotherapy is initiated. Early initiation Ethics approval and consent to participate
of immunotherapy may reduce FBDS and, more likely,
prevent long-term cognitive impairment. Not applicable.

In addition, the prognosis of a patient is largely affected Consent for publication
by the occurrence of tumor. A study in the Netherlands has
found that non-neoplastic anti-LGI1 AE is strongly associated Not applicable.
with HLA-DR7 and HLA-DRB4, suggesting that HLA-DR7 Availability of data
or HLA-DRB4 gene deletion may increase the incidence of
tumors . Therefore, the researchers have recommended Not applicable.
[25]
intensive tumor screening and long-term follow-up in patients
without HLA-DR7 or HLA-DRB4. In contrast, a British study References
has shown that HLA is not associated with tumors in anti- 1. Wang JD, Xie L, Fang X, et al., 2022, Clinical validation of
LGI1 AE . Considering the incongruity, there is an urgent the 2020 diagnostic approach for pediatric autoimmune
[22]
need for more research on HLA and tumors of these patients encephalitis in a single center. Zhonghua Er Ke Za Zhi,
to guide clinical diagnosis and treatment. 60: 786–791.
https://doi.org/10.3760/cma.j.cn112140-20220111-00039
7. Conclusions
2. Baudin P, Cousyn L, Navarro V, et al., 2021, The LGI1
Anti-LGI1 AE is a rare condition, and because it often protein: Molecular structure, physiological functions and
occurs with recent memory loss or mental and behavioral disruption-related seizures. Cell Mol Life Sci, 79: 16.
disorders, diagnosis and treatment are often delayed, https://doi.org/10.1007/s00018-021-04088-y
thus increasing the risk of poor prognosis. The diagnosis
of anti-LGI1 AE mainly depends on the history, clinical 3. Heine J, Pruss H, Kopp UA, et al., 2018, Beyond the limbic
manifestations, positive results of cerebrospinal fluid or system: Disruption and functional compensation of large-
scale brain networks in patients with anti-LGI1 encephalitis.
serum LGI1 antibody spectrum tests, and characteristic J Neurol Neurosurg Psychiatry, 89: 1191–1199.
brain MRI and F-FDG PET results. Patients with anti-
18
LGI1 AE require early diagnosis, while missed diagnosis https://doi.org/10.1136/jnnp-2017-317780
or misdiagnosis should be prevented. An early initiation of 4. Herranz-Perez V, Olucha-Bordonau FE, Morante-Redolat JM,
immunotherapy can effectively reduce mortality, seizures, et al., 2010, Regional distribution of the leucine-rich glioma
and the incidence of long-term sequelae; it can also inactivated (LGI) gene family transcripts in the adult mouse
prevent borderline encephalitis and long-term cognitive brain. Brain Res, 1307: 177–194.
impairment. More prospective studies are needed in https://doi.org/10.1016/j.brainres.2009.10.013
the future since the majority of existing studies are 5. Ohkawa T, Fukata Y, Yamasaki M, et al., 2013, Autoantibodies
retrospective studies. The review of relevant literature may to epilepsy-related LGI1 in limbic encephalitis neutralize
help improve clinicians’ understanding of the characteristic LGI1-ADAM22 interaction and reduce synaptic AMPA
manifestations of the disease. receptors. J Neurosci, 33: 18161–18174.

Volume 1 Issue 3 (2022) 7 https://doi.org/10.36922/an.v1i3.237