Screening for endocrine-disrupting chemicals in the serum and cerebrospinal fluid of patients with autoimmune encephalitis

Humans are exposed to a variety of endocrine-disrupting chemicals (EDCs), such as organophosphate esters (OPEs) and phthalate ester (PAE) metabolites. Although EDCs can cross the blood-cerebrospinal fluid barrier (BCSFB) to the brain, their effects on autoimmune encephalitis (AE) remain unclear. Therefore, the association between EDC exposure and AE were determined. The study recruited 106 patients with AE and 119 patients without AE. Using paired serum-CSF samples, we quantified 8 categories of 17 EDCs. The penetration of some EDCs was evaluated through two indices: calculated the blood-brain barrier (BBB) index and the paired serum-CSF concentration ratio. Further, we investigated the association of EDC exposure with AE by the conditional logistic regression analysis. Antioxidants, PAE metabolites, and OPEs were identified as the most dominant EDC in the ∑8 categories of EDCs. The median EDC ratios (R_EDC = EDC_CSF/EDC_Serum) ranged from 0.040 % for methyl paraben (MeP) to 3.808 % for ethyl paraben (EtP). AE patients are more likely to have BBB disruption. The associations between AE and some EDCs were found. For example, serum EtP and butyl paraben (BuP) levels [Odds Ratio (OR) = 1.69; 95 % confidence interval (CI): 1.25, 2.27; OR = 1.51; 95 % CI: 1.14, 2.00), and CSF MeP levels (OR =1.54; 95 % CI: 1.30, 1.84) were both associated with an increased risk of AE. We identified that exposure to certain environmental EDCs may be a risk factor for the development of AE. Our findings support an evidence base for the effects of specific chemicals may impair neural functions.