CD4 and relapsing-remitting multiple sclerosis: Detailed comparisons of Ki-67 expression levels in naïve CD4 T-subsets from RRMS patients and controls did show, however, increased naïve CD4 T-cell proliferation in RRMS, predominantly in the CD31-positive cells having the highest levels of CD31 expression (CD31hi cells or CD4 recent thymic emigrants—for details, see [23]) but also in CD31neg cells.