T-cell differentiation subsets in RA patients and healthy controls.

(A) Atypical differentiation in RA patients. Representative flow cytometry plots of a healthy control (57-year-old man) and a patient with RA (42-year-old woman) are shown. CD4⁺ T cells were isolated by negative selection using magnetic beads. Cell surface staining was performed with antibodies against CD45RB, CD45RA, CD45RO, and CD62L. CD45RB^bright cells are plotted as green throughout and CD45RB^dull cells as pink. Naive cells are defined by the expression of CD45RB^bright, CD45RA⁺, and CD62L⁺, as indicated by the ellipses. Memory cells are defined as CD45RB^dull, CD45RA⁻, and CD45RO^high, as indicated by the square. Compared with the healthy control, the RA patient has a smaller naive population, CD45RB^dull CD45RA⁺CD62L⁺ cells (dotted ellipse in control) are absent, and various atypical subsets have appeared (asterisk, hexagon, and arrows; see text for details). In RA patients, a significant proportion of CD45RA⁺ cells are also CD45RO^bright. (B) Naive and memory CD4⁺ T cells in RA patients. Total lymphocytes were recovered from a panel of healthy controls and RA patients. CD4⁺ T cells were separated and analyzed as described, and the proportion of naive and memory cells were plotted against age. ♦ indicate healthy controls; ⋄, patients with early RA; ▵, patients with resistant RA. Statistical analysis: controls, age versus naive T-cell proportion, r = −0.930,P < .0001; age versus memory T-cell proportion,r = +0.865, P < .0001. RA patients (both groups combined): age versus naive T-cell proportion,r = −0.480, P = .002. RA patients: age versus memory T-cell proportion, r = +0.295,P = .016.