Poor T-cell expansion in rheumatoid arthritis (RA) patients. Phenotyping of isolated CD4+ and CD8+ T-cell populations was performed using the cell surface markers CD45RB, CD45RA, CD45RO and CD62L. Differentiation subsets were defined as naïve cells (grey bars: CD45RBbright, CD45RA+, CD45RO-, CD62L+), conventional memory cells and their precursors (striped bars: CD45RBbright/dull, CD45RA-, CD45RO+, CD62L-) and post-naïve intermediates (white bars: CD45RBbright/dull, CD45RA-, CD45RO-/dull, CD62L+), as described previously . Presumed 'central' memory cells (black bars) are CD45RBdull, CD45RA+, CD45RO+ and CD62L+. Total T-cell numbers are indicated by the height of the bars. Lines across the graphs indicate the lower limits of the normal range for CD4+ and CD8+ T-cell counts. Cancer patients (n = 7 solid tumours [Table 2]) reconstitute CD4+ T cells largely by expansion of intermediate and memory subsets. This is not seen in RA patients (n = 12 at baseline and 1 month, n = 7 at 9 months; six patients from each of cohorts 2 and 3 [Table 2]). A similar expansion accounts for the 'overshoot' above baseline in CD8+ T-cells in cancer patients, whereas only a minimal transient expansion of memory CD8+ T-cells is observed in RA.