Preliminary assessment of a group of patients with very early RA, who had disease duration of less than six weeks and had received no DMARD therapy, also indicated a decrease in IgD+CD27+ pre-switch memory B cells and is consistent with the conclusion that this abnormality in memory B cell homeostasis is characteristic of RA independent of disease duration and DMARD therapy (R Moura and JE Fonseca, unpublished data). Here, CD27 is linked to rheumatoid arthritis.