CD4 and rheumatoid arthritis: The proportion of naïve (TNai) CD45RO−CCR7+, effector memory (TEM) CD45RO+CCR7−, central memory (TCM) CD45RO+CCR7+, and effector memory revertant RA+(TEMRA) CD45RO−CCR7− CD4+ and CD8+ T cells were measured by flow cytometry.