There is currently an ongoing phase II clinical trial with rozanolixizumab (ClinicalTrials.gov Identifier: NCT04875975), a high-affinity human neonatal FC receptor (IgG4P) monoclonal antibody (IgG4P), developed to reduce pathogenic IgG in autoimmune and alloimmune diseases, such as encephalitis with anti-LGI1 antibodies. This evidence concerns the gene LGI1 and viral encephalitis.