362. THE ROLE OF NEUTROPHIL MYELOPEROXIDASE AND THE NEURONAL INJURY MARKER NEUROFILAMENT LIGHT CHAIN IN COVID-19 INFECTED PATIENTS

Abstract Background Myeloperoxidase (MPO) has been reported as one of a reactive oxygen species (ROS) producing hypochlorous acid (HOCl) and involved in clinical deterioration and fatality in COVID-19-infected patients [1]. It is not clear the relation between MPO and neurointegrity measured from peripheral blood of neurofilament light chain (NfL) levels. Aims & Objectives In order to realize the role of MPO in COVID-19 infected patients, this study analyzed MPO and brain neuronal injury indicator, NfL in COVID-19-infected patients from Taiwan Biobank. Method This study measured bioindicators of MPO and NFL in plasma samples obtained from 381 COVID-19-infected patients. These samples were obtained from the National Health Research Institutes (NHRI) Biobank, with participants recruited from 29 hospitals across Taiwan. The concentrations of MPO and NFL were measured by immunoassays. Statistical analyses included the general linear mode (GLM) to analyze the medical record and discharge diagnosis, and the multiple comparison method of Tukey-Kramer. To identify differences in plasma MPO levels below and above 292 (ng/ml), the GLM was employed for continuous variables, and logistic regression analysis for categorical variables. Results The average plasma MPO and NFL levels were 196.81 ± 287.3 ng/ml and 14.82 ± 20.86 pg/ml, respectively among these 381 COVID-19-infected patients. Unlike plasma NFL was correlated with age, plasma MPO was mainly correlated with lung disease when patients were discharged from the hospital (general linear model, P=0.003), where the patient with lung disease demonstrated higher levels of MPO than no lung disease COVID-19-infected patients (307.99 ± 347.12 vs. 180.0 ± 273.9). The patients with higher MPO level (higher than the average of hospitalized MPO level 292 ng/ml), demonstrated with longer hospital stay (P<0.0001), higher percentage of hospitalization (logistic regression analysis, P<0.0001), lung diseases in discharge diagnosis (P=0.004), and types of chronic disease (P=0.014). The elevation of NFL and MPO along the confirmed diagnosis indicated that NFL level was increased at 1-7 days, but MPO was increased at 8-30 days. These results indicated a pathological process where the brain neuronal injury was the first hit and then the MPO produced of HOCl enhanced the respiratory inhibition. These may lead to clinical deterioration and fatality in COVID-19-infected patients. Discussion & Conclusions This study confirmed that MPO involved in the severe consequences after COVID-19 infection. However, its increase mainly affected the lung tissue and correlated with the lung disease of patients. The pathological process indicated that brain injury indicated by NFL is the first hit of the viral infection, and then the lung tissue damages caused by MPO. Inhibition of MPO might be able to reduce the lung tissue damages among the COVID-19 infected patients if they survived from the first brain injury. This study conducted additional screening of psychiatric drugs to identify potential treatments for elevated MPO levels.