Blood–brain barrier integrity disruption linked to brain lesions and relapse prediction in Southern Chinese anti-NMDAR encephalitis patients

Abstract

Objective This study aims to investigate the characteristic brain abnormalities in Southern Chinese patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis and to explore their association with blood–brain barrier (BBB) disruption and clinical implications. Methods This study retrospectively analyzed 80 cases of anti-NMDAR encephalitis. Patients were divided into a group with abnormal brain MRI (= 35) and a group with normal brain MRI (= 45). The extent of BBB disruption was assessed using the albumin quotient (Qalb), defined as the cerebrospinal fluid (CSF)-to-serum albumin ratio. Disease severity was evaluated using the modified Rankin Scale (mRS). Patients were further categorized into a relapse group and a non-relapse group based on post-discharge relapse status. Key predictive factors were identified through multivariate regression analysis. Results Brain MRI abnormalities were observed in 43.75% (35/80) of the anti-NMDAR encephalitis patients. Among these, typical MRI findings of anti-NMDAR encephalitis abnormalities were present in 26 patients (32.5% of the total cohort). Brain MRI abnormalities were significantly associated with abnormal BBB permeability (42.9% vs. 13.3%,= 0.003). Multivariate logistic regression analysis identified two independent predictive factors for brain MRI abnormalities: BBB dysfunction (OR = 4.088, 95% CI: 1.031–16.213,= 0.045) and time from symptom onset to first-line immunotherapy (OR = 1.041, 95% CI: 1.001–1.083,= 0.045). Furthermore, receiver operating characteristic (ROC) curve analysis demonstrated that the combined model of BBB dysfunction and time from symptom onset to first-line immunotherapy exhibited favorable predictive performance, with an area under the curve (AUC) of 0.745 (95% CI: 0.634–0.857). BBB dysfunction was closely associated with multi-regional cerebral involvement (= 0.002). Further Spearman correlation analysis showed that impaired BBB integrity correlated with greater MRI lesion severity and broader lesional distribution (= 0.003). In binary logistic regression analysis adjusting for mRS score, positive oligoclonal bands (OCBs) were identified as a potential predictor of relapse, with an OR of 7.991 (95% CI: 1.242–51.411,= 0.029). The AUC was 0.730 (95% CI: 0.542–0.918), indicating moderate predictive performance. Conclusion Abnormal BBB permeability is an independent risk factor for structural abnormalities on brain MRI and is positively correlated with the extent of MRI abnormalities. CSF OCB positivity is a risk factor for disease relapse. These findings may inform brain injury assessment, relapse risk stratification, and individualized treatment in patients with anti-NMDAR encephalitis.