CD70 and systemic lupus erythematosus: Ligation of CD70 to CD27 induces release of soluble CD27 (sCD27) and it is indeed interesting that increased soluble CD27 level is a hallmark of diverse autoimmune conditions with a strong link to EBV, such as in cerebrospinal fluid in MS, in synovial tissue in RA and in serum in both systemic lupus erythematosus and Sjögren's syndrome.22, 45, 46, 47, 48 We propose that the elevated CD70 expression is an important, overlooked feature of EBV-infected B cells and that the CD27/CD70 axis may be relevant in the association between EBV and MS.