CD4 and rheumatoid arthritis: We studied subsets of CD4+ and CD8+ T cells in a subgroup of young and older individuals (n = 80): naive (CD45RA+, CCR7+), central memory (CD45RA−, CCR7+), effector memory (CD45RA−, CCR7−), and effector memory RA (CD45RA+, CCR7-).