Clinical characteristics, long-term functional outcomes and relapse of anti-LGI1/Caspr2 encephalitis: a prospective cohort study in Western China

OBJECTIVE: To study the clinical characteristics of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis and anti-contactin-associated protein-like 2 (Caspr2) encephalitis and to investigate factors associated with poor long-term neurological functional outcomes and relapse among patients in western China. METHODS: In this single-center prospective cohort study, we consecutively enrolled patients with anti-LGI1 encephalitis and anti-Caspr2 encephalitis from April 2014 to February 2021. Patient outcomes were assessed using the modified Rankin scale. Predictors of long-term functional outcomes and relapse were analyzed. RESULTS: Forty-four anti-LGI1 encephalitis patients [median age: 44 years, range: 18–82 years; females: 25 (56.8%)], 35 anti-Caspr2 encephalitis patients [median age: 43 years, range: 14–80 years; females: 19 (54.3%)], and 5 dual-positive patients [median age: 44 years, range: 36–58 years; females: 5 (100%)] were enrolled. Overall, 86.4% anti-LGI1 encephalitis patients and 80% anti-Caspr2 encephalitis had a favorable neurological functional outcome (mRS 0-2). Tumor occurrence and weight loss were associated with poor long-term functional outcomes in anti-LGI1 encephalitis, whereas in anti-Caspr2 encephalitis, predictors included behavioral disorder at acute phase, abnormalities in brain magnetic resonance imaging, higher modified Rankin scale scores at onset, poor response to the initial immunotherapy at 4 weeks, age at onset<30 years, and relapse (p<0.05). Overall, 13.6% of anti-LGI1 encephalitis patients and 20% of anti-Caspr2 encephalitis patients had at least one relapse. Sleep disorder at the acute phase was the risk factor of relapse in anti-LGI1 encephalitis, while female, age at onset <30 years, and behavioral disorder at acute phase were the risk factors of relapse in anti-Caspr2 encephalitis (log rank p<0.05). CONCLUSION: The clinical characteristics such as age, gender, and tumor occurrence rates of anti-LGI1 encephalitis and anti-Caspr2 encephalitis in western China are different from those in the Western countries. Most patients in our study had favorable long-term functional outcomes. The relapse rates are still high in both types of encephalitis, which warrants caution.