CLEC4C and systemic lupus erythematosus: Litifilimab (BIIB059) is a humanised IgG1 monoclonal antibody targeting blood dendritic cell antigen 2 (BDCA2) reducing, among other cytokines, plasmatocytoid dendritic cells’ type I IFN production, which has already proved efficacious in a phase II trial of CLE patients.80 Phase III studies, in SLE and CLE are awaited to further assess its efficacy.81–84