ISG15 and systemic lupus erythematosus: In the B cell subset containing most autoreactive BCR sequences (memory-like subset A6), autoimmune features were also noted on the transcriptional level including upregulation of ISG15 and CD80. ISG15 expression is an autoimmune feature of memory-like B cells from SLE patients (Care et al., 2016), and CD80+ B cells can rapidly differentiate into antibody-secreting cells upon rechallenge without generating GC reactions (Zuccarino-Catania et al., 2014).