Open Access

Background Coronavirus disease 2019 (COVID-19) is an infection which can affect the central nervous system. In this study, we sought to investigate associations between neuroimaging findings with clinical, demographic, blood and cerebrospinal fluid (CSF) parameters, pre-existing conditions and the severity of acute COVID-19. Materials and methods Retrospective multicenter data retrieval from 10 university medical centers in Germany, Switzerland and Austria between February 2020 and September 2021. We included patients with COVID-19, acute neurological symptoms and cranial imaging. We collected demographics, neurological symptoms, COVID-19 severity, results of cranial imaging, blood and CSF parameters during the hospital stay. Results 442 patients could be included. COVID-19 severity was mild in 124 (28.1%) patients (moderate n = 134/30.3%, severe n = 43/9.7%, critical n = 141/31.9%). 220 patients (49.8%) presented with respiratory symptoms, 167 (37.8%) presented with neurological symptoms first. Acute ischemic stroke (AIS) was detected in 70 (15.8%), intracranial hemorrhage (IH) in 48 (10.9%) patients. Typical risk factors were associated with AIS; extracorporeal membrane oxygenation therapy and invasive ventilation with IH. No association was found between the severity of COVID-19 or blood/CSF parameters and the occurrence of AIS or IH. Discussion AIS was the most common finding on cranial imaging. IH was more prevalent than expected but a less common finding than AIS. Patients with IH had a distinct clinical profile compared to patients with AIS. There was no association between AIS or IH and the severity of COVID-19. A considerable proportion of patients presented with neurological symptoms first. Laboratory parameters have limited value as a screening tool.

The role of ubiquitin-mediated degradation mechanisms in the pathogenesis of diffuse large B-cell lymphoma (BCL) and follicular lymphoma is not completely understood. We show that conditional deletion of the E3 ubiquitin ligase Fbxo45 in germinal center B cells results in B-cell lymphomagenesis in homozygous (100%) and heterozygous (48%) mice. Mechanistically, FBXO45 targets the RHO guanine exchange factor ARHGEF2/GEF-H1 for ubiquitin-mediated degradation. Double genetic ablation of Fbxo45 and Arhgef2 ameliorated lymphoma formation. Transgenic knock-in mice harboring a GEF-H1 mutant unable to bind FBXO45 develop BCLs with ∼50% penetrance. Genome sequencing in human lymphomas identified mutually exclusive FBXO45 copy-number losses and ARHGEF2 gains, with combined frequencies ranging from 26.32% in follicular lymphoma to 45.12% in diffuse large BCL. Notably, FBXO45 silencing enhances sensitivity to MEK1/2 inhibition. These results identify FBXO45 and ARHGEF2 as a novel tumor suppressor and oncogene pair involved in the pathogenesis of BCLs with important implications for targeted therapies.